Cannot use curl to send JSON-RPC commands · Issue #1504 ...

Are all these JSON-RPC commands supported by a pruned node? /r/Bitcoin

Are all these JSON-RPC commands supported by a pruned node? /Bitcoin submitted by ABitcoinAllBot to BitcoinAll [link] [comments]

Hey, r/Bitcoin and Node.js developers, I created an open-source Express middleware plugin that easily maps JSON-RPC commands to any url for rapid development.

Hey, Bitcoin and Node.js developers, I created an open-source Express middleware plugin that easily maps JSON-RPC commands to any url for rapid development. submitted by NielDLR to Bitcoin [link] [comments]

Power of the Command Line (bitcoin-cli, hwi, electrum, trezorctl)

I think some of the console tools available with HW wallets today are greatly under utilized. Here's a quick write-up on how to create and sign a TXN very similar to 43d27...1fc06 found on the SLIP-14 wallet. I'll be using TrezorCTL, Electrum, and HWI for the signing. I won't go much into the setup or install, but feel free to ask if you have questions about it. Note, you don't have to use all three of these. Any one will produce a valid signed TXN for broadcast. I just showed how to do it three ways. Whats more some of the Electrum and HWI steps are interchangeable.
ColdCard also has a utility called ckcc that will do the sign operation instead of HWI, but in many ways they are interchangeable. KeepKey and Ledger both have libraries for scripted signing but no one-shot, one-line console apps that I know of. But HWI and Electrum of course work on all four.

TrezorCTL

This is the what most would think of to use to craft and sign TXNs, and is definitely very simple. The signing uses a script called build_tx.py to create a JSON file that is then used by the btc sign-tx command. The whole process is basically:
  1. tools/build_tx.py | trezorctl btc sign-tx -
This just means, take the output of build_tx and sign it. To copy 43d27...1fc06, I wrote a small script to feed build_tx, so my process looks like:
  1. ~/input.sh | tools/build_tx.py | trezorctl btc sign-tx -
But it's all very simple. Note... I used TrezorCTL v0.12.2 but build_tx.py version 0.13.0 1.

input.sh

```

!/bin/bash

secho() { sleep 1; echo $*}
secho "Testnet" # coin name secho "tbtc1.trezor.io" # blockbook server and outpoint (below) secho "e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00:0" secho "m/84'/1'/0'/0/0" # prev_out derivation to signing key secho "4294967293" # Sequence for RBF; hex(-3) secho "segwit" # Signature type on prev_out to use secho "" # NACK to progress to outs secho "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3" # out[0].addr secho "10000000" # out[1].amt secho "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu" # out[1].addr secho "20000000" # out[1].amt secho "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x" # out[2].addr secho "99999694" # out[2].amt secho "" # NACK to progress to change secho "" # NACK to skip change secho "2" # txn.version secho "0" # txn.locktime ```

Electrum

Electrum is one of the better GUI wallets available, but it also has a pretty good console interface. Like before you need your Trezor with the SLIP-14 wallet loaded and paired to Electrum. I'll assume Electrum is up and running with the Trezor wallet loaded to make things simple.
Like with TrezorCTL, Electrum feeds on a JSON file, but unlike TrezorCTL it needs that JSON squished into the command line. This is a simple sed command, but I won't bore you with the details, but just assume that's done. So the process in Electrum (v4.0.3) looks like:
  1. electrum serialize (create psbt to sign)
  2. electrum --wallet signtransaction (sign said psbt)
Still pretty simple right! Below is the JSON I smushed for #1

txn.json

{ "inputs": [{ "prevout_hash":"e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00", "prevout_n": 0, "value_sats": 129999867 }], "outputs": [{ "address": "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3", "value_sats": 10000000 },{ "address": "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu", "value_sats": 20000000 },{ "address": "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x", "value_sats": 99999694 }]}

HWI

HWI is an unsung hero in my book. It's a very small clean and simple interface between HW wallets and Bitcoin Core. It currently supports a good range of HW wallets. It keeps itself narrowly focused on TXN signing and offloads most everything else to Bitcoin Core. Again, I'll assume you've imported your Trezor keypool into Core and done the requisite IBD and rescan. And if you don't have the RPC enabled, you can always clone these commands into the QT-console.
To sign our TXN in HWI (v1.1.2), we will first need to craft (and finalize) it in Bitcoin Core (0.21.1). Like in Electrum, we will have to use simple sed to smush some JSON into command arguments, but I'll assume you have that covered. It will take an inputs.json and an outputs.json named separately.
  1. bitcoin-cli createpsbt (create psbt)
  2. bitcoin-cli -rpcwallet= walletprocesspsbt (process psbt)
  3. hwi -f signtx (sign psbt)
  4. bitcoin-cli -rpcwallet= finalizepsbt (get a signed TXN from psbt)
A little more involved, but still nothing too bad. Plus this gives you the full power of Bitcoin Core including integrations with LND (lightning).

inputs.json

[{ "txid": "e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00", "vout": 0 }]

outputs.json

[{ "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3": 0.10000000 },{ "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu": 0.20000000 },{ "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x": 0.99999694 }]

Conclusion

This may all seem like very low level coding, but is surprisingly simple once you get a knack for it. Whats more, all these platforms support testnet which allows you to practice with valueless coins until you get the hang of it. And, like many things in bitcoin, this is all (mostly) python, which is one of the easier languages to learn.
Enjoy
Footnotes
1 - https://github.com/trezotrezor-firmware/issues/1296
submitted by brianddk to Bitcoin [link] [comments]

What does "bin/bitcoin-wallet" and other binaries do?

I'm old, and haven't run Bitcoin Core since the 80's, when it was just bitcoind and bitcon-qt.
Can someone tell me what these files are and what they do, because a) they're not mentioned in the readme.md, and b) Google is absolutely useless for searches like "bin/bitcoin-wallet", returning patronising results like "What is a bitcoin wallet?"
bin/bitcoin-cli // command-line bitcoin client bin/bitcoind // bitcoin daemon bin/bitcoin-qt // gui client bin/bitcoin-tx // ?? bin/bitcoin-wallet // ?????? 
Thanks.
submitted by textreply to Bitcoin [link] [comments]

Power of the Command Line (bitcoin-cli, hwi, electrum, trezorctl)

I think some of the console tools available with HW wallets today are greatly under utilized. Here's a quick write-up on how to create and sign a TXN very similar to 43d27...1fc06 found on the SLIP-14 wallet. I'll be using TrezorCTL, Electrum, and HWI for the signing. I won't go much into the setup or install, but feel free to ask if you have questions about it. Note, you don't have to use all three of these. Any one will produce a valid signed TXN for broadcast. I just showed how to do it three ways. Whats more some of the Electrum and HWI steps are interchangeable.

TrezorCTL

This is the what most would think of to use to craft and sign TXNs, and is definitely very simple. The signing uses a script called build_tx.py to create a JSON file that is then used by the btc sign-tx command. The whole process is basically:
  1. tools/build_tx.py | trezorctl btc sign-tx -
This just means, take the output of build_tx and sign it. To copy 43d27...1fc06, I wrote a small script to feed build_tx, so my process looks like:
  1. ~/input.sh | tools/build_tx.py | trezorctl btc sign-tx -
But it's all very simple. Note... I used TrezorCTL v0.12.2 but build_tx.py version 0.13.0 1.

input.sh

```

!/bin/bash

secho() { sleep 1; echo $*}
secho "Testnet" # coin name secho "tbtc1.trezor.io" # blockbook server and outpoint (below) secho "e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00:0" secho "m/84'/1'/0'/0/0" # prev_out derivation to signing key secho "4294967293" # Sequence for RBF; hex(-3) secho "segwit" # Signature type on prev_out to use secho "" # NACK to progress to outs secho "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3" # out[0].addr secho "10000000" # out[1].amt secho "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu" # out[1].addr secho "20000000" # out[1].amt secho "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x" # out[2].addr secho "99999694" # out[2].amt secho "" # NACK to progress to change secho "" # NACK to skip change secho "2" # txn.version secho "0" # txn.locktime ```

Electrum

Electrum is one of the better GUI wallets available, but it also has a pretty good console interface. Like before you need your Trezor with the SLIP-14 wallet loaded and paired to Electrum. I'll assume Electrum is up and running with the Trezor wallet loaded to make things simple.
Like with TrezorCTL, Electrum feeds on a JSON file, but unlike TrezorCTL it needs that JSON squished into the command line. This is a simple sed command, but I won't bore you with the details, but just assume that's done. So the process in Electrum (v4.0.3) looks like:
  1. electrum serialize (create psbt to sign)
  2. electrum --wallet signtransaction (sign said psbt)
Still pretty simple right! Below is the JSON I smushed for #1

txn.json

{ "inputs": [{ "prevout_hash":"e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00", "prevout_n": 0, "value_sats": 129999867 }], "outputs": [{ "address": "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3", "value_sats": 10000000 },{ "address": "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu", "value_sats": 20000000 },{ "address": "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x", "value_sats": 99999694 }]}

HWI

HWI is an unsung hero in my book. It's a very small clean and simple interface between HW wallets and Bitcoin Core. It currently supports a good range of HW wallets. It keeps itself narrowly focused on TXN signing and offloads most everything else to Bitcoin Core. Again, I'll assume you've imported your Trezor keypool into Core and done the requisite IBD and rescan. And if you don't have the RPC enabled, you can always clone these commands into the QT-console.
To sign our TXN in HWI (v1.1.2), we will first need to craft (and finalize) it in Bitcoin Core (0.21.1). Like in Electrum, we will have to use simple sed to smush some JSON into command arguments, but I'll assume you have that covered. It will take an inputs.json and an outputs.json named separately.
  1. bitcoin-cli createpsbt (create psbt)
  2. bitcoin-cli -rpcwallet= walletprocesspsbt (process psbt)
  3. hwi -f signtx (sign psbt)
  4. bitcoin-cli -rpcwallet= finalizepsbt (get a signed TXN from psbt)
A little more involved, but still nothing too bad. Plus this gives you the full power of Bitcoin Core including integrations with LND (lightning).

inputs.json

[{ "txid": "e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00", "vout": 0 }]

outputs.json

[{ "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3": 0.10000000 },{ "tb1q9l0rk0gkgn73d0gc57qn3t3cwvucaj3h8wtrlu": 0.20000000 },{ "tb1qejqxwzfld7zr6mf7ygqy5s5se5xq7vmt96jk9x": 0.99999694 }]

Conclusion

This may all seem like very low level coding, but is surprisingly simple once you get a knack for it. Whats more, all these platforms support testnet which allows you to practice with valueless coins until you get the hang of it. And, like many things in bitcoin, this is all (mostly) python, which is one of the easier languages to learn.
Enjoy
Footnotes
1 - https://github.com/trezotrezor-firmware/issues/1296
submitted by brianddk to TREZOR [link] [comments]

BCH JSON RPC Calls List?

Hi all, trying to find documentation for the list of JSON RPC calls for Bitcoin Cash. This is as close as I can get, and it says it's outdated.
submitted by jeffthedunker to Bitcoincash [link] [comments]

I built lightningd, and now am running it, and running into this problem where bcli seems to be returning wrong json (with bitcoind running too)

So I have confirmed that the bitcoin-cli.exe is being invoked, with the arguments shown. But I am not sure why this error is coming up. If I run bitcoin-cli.exe from command line, I can easily get replies for command like getblockchaininfo, which confirms that bitcoind is running.

Here is what I get as output of lightningd command:
2020-08-30T17:35:53.634Z INFO plugin-bcli: bitcoin-cli initialized and connected to bitcoind. /uslocal/bin/../libexec/c-lightning/plugins/bcli error: bad response to getrawblockbyheight (bad 'result' field), response was {"jsonrpc":"2.0","id":8,"error":{"code":400,"message":"bitcoin-cli.exe -datadir=G:\\\\.bitcoin -rpcconnect=127.0.0.1 -rpcport=8332 -rpcuser=... -rpcpassword=... getblockhash 646000: bad JSON: bad blockhash (00000000000000000001ef19be9c9879c6e9aa6241a096f543109e2a34397936\r\n)"} } 
Not sure why I am seeing this problem.
Update: I got it running. Now I see this
2020-08-30T23:45:47.611Z INFO plugin-bcli: bitcoin-cli initialized and connected to bitcoind. 2020-08-30T23:45:48.728Z INFO lightningd: -------------------------------------------------- 2020-08-30T23:45:48.729Z INFO lightningd: Server started with public key 03c7505d1ac56441f234025cd348743cddff147f9356e6296820d5e95d1a56b29d, alias GREENTOLL (color #03c750) and lightningd v0.9.0-197-gdd8cd81-modded 
I've no clue what I am doing, but will continue digging more.
submitted by parakite to lightningnetwork [link] [comments]

How-to: setup your multisignature Cold wallet in Bitcoin Core 0.20 (highest security setup)

Last release of Core is amazing !
The main new feature is sortedmulti descriptor. This allows you to import your multisig setup in Core almost as if it was Electrum when combine to the new PSBT export in GUI !
As it needs command line and some weird checksum, you also need to input very long command in the console and if you made a mistake, you cannot copy the last command you made. So take your time when the commands are long to check everything and don't miss anything, use copy paste before validating the long command. You only have to do this once fortunately :)
I detail here how you do it with a k of n setup, good luck:
And you are DONE ! You should get the exact same addresses than Electrum and you can created receiving addresses in Qt ! To send money, just go to the send section, use the new coin control feature and export a partially signed transaction. You can use HWI or Electrum to sign it with your hardware wallets !
Notice: You can import more or less than 2000 addresses of each type. If less, blockchain rescan is faster but you may need to redo what we have done here later when all addresses will have been used once. If more, it is the contrary.

You now have the most possibly secure setup in one software: multisig with hardware on the full node wallet. When Bitcoin Core 0.21.0 will be out, we will also have native descriptor wallet so maybe we will have HD version of this. But for now, this is the best you can do ! Enjoy :)

P.S. : if you like doing things in one shot you can do the last two steps in one big command: importmulti '[{"desc": "wsh(sortedmulti(k,[path1]xpub1.../0/*,[path2]xpub2.../0/*,...,[pathn]xpubn/0/*))#check_sum0", "timestamp": birth_timestamp, "range": [0,2000], "watchonly": true, "keypool": true}, {"desc": "wsh(sortedmulti(k,[path1]xpub1.../1/*,[path2]xpub2.../1/*,...,[pathn]xpubn/1/*))#check_sum1", "timestamp": birth_timestamp, "range": [0,2000], "watchonly": true, "internal": true}]'
submitted by Pantamis to Bitcoin [link] [comments]

Bitcoin price quote for Linux shell

I love to work with the Linux shell (bash; Linuxmint/Ubuntu) all day, and from time to time I want to know the current price of Bitcoin and Ether. So I created a simple Linux shellscript, which displays both cross-prices to USD and EUR within the shell after typing in "btc". I know that I could use the web for this task, but I like it this way and I also don't want to be constantly informed (i.e. with an app on the smartphone).
Here it is, let me know if you like it.
#!/bin/bash # this simple Linux shell script uses the "jq" command line # JSON data processor pls. install "jq" first (sudo apt # install jq) then save the skript with an editor as i.e. # "btc" under a path for executables, (i.e. ~/.local/bin/) # and make it executable ("sudo chmod +x btc"). The script # uses market data from the kraken api; pls. feel free to # use any other api. The script displays the current price # of Bitcoin and Ether in USD and EUR. If you don't like # the colors, try playing around with the "tput setaf x" # (color of characters) and "tput setab x" (background # color); you might find the information frome here: # https://stackoverflow.com/questions/5947742/how-to-change-the-output-color-of-echo-in-linux # useful. Enjoy! JSN1=$(curl -s "https://api.kraken.com/0/public/Ticker?pair=XBTUSD") JSN2=$(curl -s "https://api.kraken.com/0/public/Ticker?pair=XBTEUR") JSN3=$(curl -s "https://api.kraken.com/0/public/Ticker?pair=ETHUSD") JSN4=$(curl -s "https://api.kraken.com/0/public/Ticker?pair=ETHEUR") QRAW1=$(echo $JSN1 | jq ".result.XXBTZUSD.c[0]") QRAW2=$(echo $JSN2 | jq ".result.XXBTZEUR.c[0]") QRAW3=$(echo $JSN3 | jq ".result.XETHZUSD.c[0]") QRAW4=$(echo $JSN4 | jq ".result.XETHZEUR.c[0]") RGX='\"\([0-9]\+\)\.[0-9]\+\"' Q1=$(echo $QRAW1 | sed "s/${RGX}$/\1/g") Q2=$(echo $QRAW2 | sed "s/${RGX}$/\1/g") Q3=$(echo $QRAW3 | sed "s/${RGX}$/\1/g") Q4=$(echo $QRAW4 | sed "s/${RGX}$/\1/g") RED=`tput setaf 1` GREEN=`tput setaf 2` WHITEBACK=`tput setab 7` CYANBACK=`tput setab 6` BOLD=`tput bold` RESET=`tput sgr0` echo "${WHITEBACK}${BOLD}${RED}Bitcoin: $""$Q1"" €""$Q2${RESET}"" ${BOLD}${CYANBACK}${GREEN}Ether: $""$Q3"" €""$Q4${RESET}" 
submitted by fatrattombala to Bitcoin [link] [comments]

Are there any bitcoin-tx tutorials?

This:
https://bitcoin.org/en/developer-examples
Has nothing on bitcoin-tx and I can't find any tutorials on it.
I'd like to figure out how to create raw transactions and do them myself.
Why?
Because freedom and fuck fiat.
Does anyone know of a source that can teach me to use bitcoin-tx.
And yes - I'm fairly familiar with bitcoin-cli.
Thanks in advance for any help.
submitted by Pure_Evil_666 to Bitcoin [link] [comments]

Cruzbit Is Celebrating Its First Year

The cruzbit blockchain has now been operational for its first full year. Block 0 was mined on Saturday, June 22, 2019 at 3:12:36 AM GMT, and the network has since mined just short of 67,500 blocks without notable issue.
Cruzbit is an all new codebase written in Go, designed to adopt the same behaviors as Bitcoin but with a strict focus on simplicity. The protocol uses established and mostly ubiquitous technologies such as WebSockets for connection, and JSON objects for both block and transaction storage, as well as in message transmission. The overarching principal is that developers should not need to spend their time becoming experts in the project in order to start developing upon it.
The community invite you to have a look at our project, and help us celebrate our first successful year!
submitted by jstnryan to cryptodevs [link] [comments]

When I restart my bot, it wipes my JSON file and makes it empty [discord.py]

So I'm trying to make a currency command and I store the amount of currency they have in a JSON file. When I restart the bot though, the JSON file becomes empty! I have no idea why this might be happening and it doesn't return an error. Could anyone explain this? Thanks in advance!
if message.content.lower().startswith(prefix + 'bal'): data = {} try: with open('money.json', 'r') as file: data = json.load(file) except ValueError: print(str(message.author) + " has no money") if str(message.author) in data: try: embed = discord.Embed(title = "Balance", description='Your balance in Killer\'s economy!' , color=embed_colors[random.randint(0, 43)]) embed.set_author(name = message.author, icon_url = message.author.avatar_url) embed.add_field(name = "Bitcoins", value = "You have " + str(data[str(message.author)]['money']) + " bitcoins") await message.channel.send(embed = embed) except KeyError: embed = discord.Embed(title = "Balance", description='Your balance in Killer\'s economy!' , color=embed_colors[random.randint(0, 43)]) embed.set_author(name = message.author, icon_url = message.author.avatar_url) embed.add_field(name = "Bitcoins", value = "You have 0 bitcoins") await message.channel.send(embed = embed) else: embed = discord.Embed(title = "Balance", description='Your balance in Killer\'s economy!' , color=embed_colors[random.randint(0, 43)]) embed.set_author(name = message.author, icon_url = message.author.avatar_url) embed.add_field(name = "Bitcoins", value = "You have 0 bitcoins") await message.channel.send(embed = embed) 
submitted by Mike6872 to Discord_Bots [link] [comments]

Coins possibly stuck in tumbler

I believe some of my coins may be stuck because the tumbler crashed before completing. I use the UI to access my wallet and run the tumber, however it says that I have very little coins while bitcoin core is showing much more in watch only.
I looked on reddit for any possible fixes and I was told to run this:
 python wallet-tool.py -m 15 my-wallet-file.json 
The commenter said that the coins are most likely stuck in a higher mixdepth so running this will increase the maximum mixdepth. Unfortunately this doesn't appear to do anything for me, or I'm just not smart enough to see what was done. I've included what happens when I run this command below
(jmvenv) [email protected]:~/joinmarket-clientservescripts$ python wallet-tool.py -m 15 wallet.json User data location: /home/caleb/.joinmarket/ Enter wallet decryption passphrase: Traceback (most recent call last): File "wallet-tool.py", line 9, in  jmprint(wallet_tool_main("wallets"), "success") File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet_utils.py", line 1242, in wallet_tool_main wallet_password_stdin=options.wallet_password_stdin, gap_limit=options.gaplimit) File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet_utils.py", line 1133, in open_test_wallet_maybe return open_wallet(path, mixdepth=max_mixdepth, **kwargs) File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet_utils.py", line 1179, in open_wallet wallet = wallet_cls(storage, **kwargs) File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet.py", line 1031, in __init__ super(ImportWalletMixin, self).__init__(storage, **kwargs) File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet.py", line 1282, in __init__ super(BIP32Wallet, self).__init__(storage, **kwargs) File "/home/caleb/joinmarket-clientservejmclient/jmclient/wallet.py", line 335, in __init__ .format(self.max_mixdepth)) Exception: Effective max mixdepth must be at most 4! 
Any suggestions would be appreciated.
submitted by DecentMidLaner to joinmarket [link] [comments]

[How-To] Crafting an offline TXN with the trezorlib python API

With the rollout of the new 0.12.0 Trezor API, I thought it might be time to update some of my old offline_txn scripts. The following is about 80 lines of python that will craft and sign a VERY simple transaction on Testnet.
The new rollout also comes with some new tools. The build_tx.py that is useful in conjunction with the trezorctl sign_tx command.
Both of the methods below will produce a signed TXN that can then be imported into Electrum using the "Tools -> Load transaction -> From text" command.
Note: u/Crypto-Guide has a good walkthrough for installing trezorlib in Windows if you haven't already done that.

Example of using trezorctl btc sign-tx

This example uses the build_tx.py script to build JSON to feed to the sign-tx command. You will need to download the build_tx.py file from github. It is not automatically installed with the trezor package.
```

python build_tx.py | trezorctl btc sign-tx -

Coin name [Bitcoin]: Testnet Blockbook server [btc1.trezor.io]: tbtc1.trezor.io
Previous output to spend (txid:vout) []: e294c4c172c3d87991...060fad1ed31d12ff00:0 BIP-32 path to derive the key: m/84'/1'/0'/0/0 Input amount: 129999866 Sequence Number to use (RBF opt-in enabled by default) [4294967293]: Input type (address, segwit, p2shsegwit) [segwit]:
Previous output to spend (txid:vout) []:
Output address (for non-change output) []: 2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3 Amount to spend (satoshis): 129999706
Output address (for non-change output) []: BIP-32 path (for change output) []: Transaction version [2]: Transaction locktime [0]: Please confirm action on your Trezor device.
Signed Transaction: 0200000000010100ff121dd31ead0f06...f279b642d85c48798685f86200000000 ```

Example of using crafting a TXN using trezorlib directly

If your good with python, or want to see how everything works under the hood, here's 80 lines of python to generate a similar signed transaction.
```python

!/usbin/env python3

[repo] https://github.com/brianddk/reddit ... python/offline_txn.py

[req] pip3 install trezor

from trezorlib import btc, messages as proto, tools, ui from trezorlib import MINIMUM_FIRMWARE_VERSION as min_version from trezorlib.client import TrezorClient from trezorlib.transport import get_transport from trezorlib.btc import from_json from json import loads from decimal import Decimal from sys import exit

Tested with SLIP-0014 allallall seed (slip-0014.md)

User Provided Fields; These are pulled from test scripts

CHANGE THESE!!!

coin = "Testnet"

Get legacy UTXO prev_txn hex from blockbook server. For example:

https://tbtc1.trezor.io/api/tx-specific/ \

e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00

in1_prev_txn_s = '{"txid":' \ '"e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00"}'
in1_prev_index = 0 in1_addr_path = "m/84'/1'/0'/0/0" # allallall seed in1_amount = 129999867 out1_address = "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3" out1_amount = in1_amount - 192

Defaults

tx_version = 2 tx_locktime = 0 sequence = 4294967293

Code

in1_prev_txn_j = loads(in1_prev_txn_s, parse_float=Decimal) in1_prev_hash = in1_prev_txn_j['txid'] in1_prev_hash_b = bytes.fromhex(in1_prev_hash) device = get_transport() client = TrezorClient(transport=device, ui=ui.ClickUI())
fw_version = (client.features.major_version, client.features.minor_version, client.features.patch_version) if fw_version < min_version[client.features.model]: print("Please flash to the latest FW") exit(1)
signtx = proto.SignTx( version = tx_version, lock_time = tx_locktime )
ins = [proto.TxInputType( address_n=tools.parse_path(in1_addr_path), prev_hash=in1_prev_hash_b, prev_index=in1_prev_index, amount=in1_amount, script_type=proto.InputScriptType.SPENDWITNESS, sequence=sequence )] outs = [proto.TxOutputType( address=out1_address, amount=out1_amount, script_type=proto.OutputScriptType.PAYTOADDRESS )]
txes = None for i in ins: if i.script_type == proto.InputScriptType.SPENDADDRESS: tx = from_json(in1_prev_txn_j) txes = {in1_prev_hash_b: tx} break
_, serialized_tx = btc.sign_tx(client, coin, ins, outs, details=signtx, prev_txes=txes) client.close() print(f'{{"hex": "{serialized_tx.hex()}"}}') ```
From here, you simple take the resultant TXN hex and import it into Electrum using the "Tools -> Load transaction -> From text" clickpath
submitted by brianddk to Bitcoin [link] [comments]

FlowCards: A Declarative Framework for Development of Ergo dApps

FlowCards: A Declarative Framework for Development of Ergo dApps
Introduction
ErgoScript is the smart contract language used by the Ergo blockchain. While it has concise syntax adopted from Scala/Kotlin, it still may seem confusing at first because conceptually ErgoScript is quite different compared to conventional languages which we all know and love. This is because Ergo is a UTXO based blockchain, whereas smart contracts are traditionally associated with account based systems like Ethereum. However, Ergo's transaction model has many advantages over the account based model and with the right approach it can even be significantly easier to develop Ergo contracts than to write and debug Solidity code.
Below we will cover the key aspects of the Ergo contract model which makes it different:
Paradigm
The account model of Ethereum is imperative. This means that the typical task of sending coins from Alice to Bob requires changing the balances in storage as a series of operations. Ergo's UTXO based programming model on the other hand is declarative. ErgoScript contracts specify conditions for a transaction to be accepted by the blockchain (not changes to be made in the storage state as result of the contract execution).
Scalability
In the account model of Ethereum both storage changes and validity checks are performed on-chain during code execution. In contrast, Ergo transactions are created off-chain and only validation checks are performed on-chain thus reducing the amount of operations performed by every node on the network. In addition, due to immutability of the transaction graph, various optimization strategies are possible to improve throughput of transactions per second in the network. Light verifying nodes are also possible thus further facilitating scalability and accessibility of the network.
Shared state
The account-based model is reliant on shared mutable state which is known to lead to complex semantics (and subtle million dollar bugs) in the context of concurrent/ distributed computation. Ergo's model is based on an immutable graph of transactions. This approach, inherited from Bitcoin, plays well with the concurrent and distributed nature of blockchains and facilitates light trustless clients.
Expressive Power
Ethereum advocated execution of a turing-complete language on the blockchain. It theoretically promised unlimited potential, however in practice severe limitations came to light from excessive blockchain bloat, subtle multi-million dollar bugs, gas costs which limit contract complexity, and other such problems. Ergo on the flip side extends UTXO to enable turing-completeness while limiting the complexity of the ErgoScript language itself. The same expressive power is achieved in a different and more semantically sound way.
With the all of the above points, it should be clear that there are a lot of benefits to the model Ergo is using. In the rest of this article I will introduce you to the concept of FlowCards - a dApp developer component which allows for designing complex Ergo contracts in a declarative and visual way.

From Imperative to Declarative

In the imperative programming model of Ethereum a transaction is a sequence of operations executed by the Ethereum VM. The following Solidity function implements a transfer of tokens from sender to receiver . The transaction starts when sender calls this function on an instance of a contract and ends when the function returns.
// Sends an amount of existing coins from any caller to an address function send(address receiver, uint amount) public { require(amount <= balances[msg.sender], "Insufficient balance."); balances[msg.sender] -= amount; balances[receiver] += amount; emit Sent(msg.sender, receiver, amount); } 
The function first checks the pre-conditions, then updates the storage (i.e. balances) and finally publishes the post-condition as the Sent event. The gas which is consumed by the transaction is sent to the miner as a reward for executing this transaction.
Unlike Ethereum, a transaction in Ergo is a data structure holding a list of input coins which it spends and a list of output coins which it creates preserving the total balances of ERGs and tokens (in which Ergo is similar to Bitcoin).
Turning back to the example above, since Ergo natively supports tokens, therefore for this specific example of sending tokens we don't need to write any code in ErgoScript. Instead we need to create the ‘send’ transaction shown in the following figure, which describes the same token transfer but declaratively.
https://preview.redd.it/sxs3kesvrsv41.png?width=1348&format=png&auto=webp&s=582382bc26912ff79114d831d937d94b6988e69f
The picture visually describes the following steps, which the network user needs to perform:
  1. Select unspent sender's boxes, containing in total tB >= amount of tokens and B >= txFee + minErg ERGs.
  2. Create an output target box which is protected by the receiver public key with minErg ERGs and amount of T tokens.
  3. Create one fee output protected by the minerFee contract with txFee ERGs.
  4. Create one change output protected by the sender public key, containing B - minErg - txFee ERGs and tB - amount of T tokens.
  5. Create a new transaction, sign it using the sender's secret key and send to the Ergo network.
What is important to understand here is that all of these steps are preformed off-chain (for example using Appkit Transaction API) by the user's application. Ergo network nodes don't need to repeat this transaction creation process, they only need to validate the already formed transaction. ErgoScript contracts are stored in the inputs of the transaction and check spending conditions. The node executes the contracts on-chain when the transaction is validated. The transaction is valid if all of the conditions are satisfied.
Thus, in Ethereum when we “send amount from sender to recipient” we are literally editing balances and updating the storage with a concrete set of commands. This happens on-chain and thus a new transaction is also created on-chain as the result of this process.
In Ergo (as in Bitcoin) transactions are created off-chain and the network nodes only verify them. The effects of the transaction on the blockchain state is that input coins (or Boxes in Ergo's parlance) are removed and output boxes are added to the UTXO set.
In the example above we don't use an ErgoScript contract but instead assume a signature check is used as the spending pre-condition. However in more complex application scenarios we of course need to use ErgoScript which is what we are going to discuss next.

From Changing State to Checking Context

In the send function example we first checked the pre-condition (require(amount <= balances[msg.sender],...) ) and then changed the state (i.e. update balances balances[msg.sender] -= amount ). This is typical in Ethereum transactions. Before we change anything we need to check if it is valid to do so.
In Ergo, as we discussed previously, the state (i.e. UTXO set of boxes) is changed implicitly when a valid transaction is included in a block. Thus we only need to check the pre-conditions before the transaction can be added to the block. This is what ErgoScript contracts do.
It is not possible to “change the state” in ErgoScript because it is a language to check pre-conditions for spending coins. ErgoScript is a purely functional language without side effects that operates on immutable data values. This means all the inputs, outputs and other transaction parameters available in a script are immutable. This, among other things, makes ErgoScript a very simple language that is easy to learn and safe to use. Similar to Bitcoin, each input box contains a script, which should return the true value in order to 1) allow spending of the box (i.e. removing from the UTXO set) and 2) adding the transaction to the block.
If we are being pedantic, it is therefore incorrect (strictly speaking) to think of ErgoScript as the language of Ergo contracts, because it is the language of propositions (logical predicates, formulas, etc.) which protect boxes from “illegal” spending. Unlike Bitcoin, in Ergo the whole transaction and a part of the current blockchain context is available to every script. Therefore each script may check which outputs are created by the transaction, their ERG and token amounts (we will use this capability in our example DEX contracts), current block number etc.
In ErgoScript you define the conditions of whether changes (i.e. coin spending) are allowed to happen in a given context. This is in contrast to programming the changes imperatively in the code of a contract.
While Ergo's transaction model unlocks a whole range of applications like (DEX, DeFi Apps, LETS, etc), designing contracts as pre-conditions for coin spending (or guarding scripts) directly is not intuitive. In the next sections we will consider a useful graphical notation to design contracts declaratively using FlowCard Diagrams, which is a visual representation of executable components (FlowCards).
FlowCards aim to radically simplify dApp development on the Ergo platform by providing a high-level declarative language, execution runtime, storage format and a graphical notation.
We will start with a high level of diagrams and go down to FlowCard specification.

FlowCard Diagrams

The idea behind FlowCard diagrams is based on the following observations: 1) An Ergo box is immutable and can only be spent in the transaction which uses it as an input. 2) We therefore can draw a flow of boxes through transactions, so that boxes flowing in to the transaction are spent and those flowing out are created and added to the UTXO. 3) A transaction from this perspective is simply a transformer of old boxes to the new ones preserving the balances of ERGs and tokens involved.
The following figure shows the main elements of the Ergo transaction we've already seen previously (now under the name of FlowCard Diagram).
https://preview.redd.it/06aqkcd1ssv41.png?width=1304&format=png&auto=webp&s=106eda730e0526919aabd5af9596b97e45b69777
There is a strictly defined meaning (semantics) behind every element of the diagram, so that the diagram is a visual representation (or a view) of the underlying executable component (called FlowCard).
The FlowCard can be used as a reusable component of an Ergo dApp to create and initiate the transaction on the Ergo blockchain. We will discuss this in the coming sections.
Now let's look at the individual pieces of the FlowCard diagram one by one.
1. Name and Parameters
Each flow card is given a name and a list of typed parameters. This is similar to a template with parameters. In the above figure we can see the Send flow card which has five parameters. The parameters are used in the specification.
2. Contract Wallet
This is a key element of the flow card. Every box has a guarding script. Often it is the script that checks a signature against a public key. This script is trivial in ErgoScript and is defined like the def pk(pubkey: Address) = { pubkey } template where pubkey is a parameter of the type Address . In the figure, the script template is applied to the parameter pk(sender) and thus a concrete wallet contract is obtained. Therefore pk(sender) and pk(receiver) yield different scripts and represent different wallets on the diagram, even though they use the same template.
Contract Wallet contains a set of all UTXO boxes which have a given script derived from the given script template using flow card parameters. For example, in the figure, the template is pk and parameter pubkey is substituted with the `sender’ flow card parameter.
3. Contract
Even though a contract is a property of a box, on the diagram we group the boxes by their contracts, therefore it looks like the boxes belong to the contracts, rather than the contracts belong to the boxes. In the example, we have three instantiated contracts pk(sender) , pk(receiver) and minerFee . Note, that pk(sender) is the instantiation of the pk template with the concrete parameter sender and minerFee is the instantiation of the pre-defined contract which protects the miner reward boxes.
4. Box name
In the diagram we can give each box a name. Besides readability of the diagram, we also use the name as a synonym of a more complex indexed access to the box in the contract. For example, change is the name of the box, which can also be used in the ErgoScript conditions instead of OUTPUTS(2) . We also use box names to associate spending conditions with the boxes.
5. Boxes in the wallet
In the diagram, we show boxes (darker rectangles) as belonging to the contract wallets (lighter rectangles). Each such box rectangle is connected with a grey transaction rectangle by either orange or green arrows or both. An output box (with an incoming green arrow) may include many lines of text where each line specifies a condition which should be checked as part of the transaction. The first line specifies the condition on the amount of ERG which should be placed in the box. Other lines may take one of the following forms:
  1. amount: TOKEN - the box should contain the given amount of the given TOKEN
  2. R == value - the box should contain the given value of the given register R
  3. boxName ? condition - the box named boxName should check condition in its script.
We discuss these conditions in the sections below.
6. Amount of ERGs in the box
Each box should store a minimum amount of ERGs. This is checked when the creating transaction is validated. In the diagram the amount of ERGs is always shown as the first line (e.g. B: ERG or B - minErg - txFee ). The value type ascription B: ERG is optional and may be used for readability. When the value is given as a formula, then this formula should be respected by the transaction which creates the box.
It is important to understand that variables like amount and txFee are not named properties of the boxes. They are parameters of the whole diagram and representing some amounts. Or put it another way, they are shared parameters between transactions (e.g. Sell Order and Swap transactions from DEX example below share the tAmt parameter). So the same name is tied to the same value throughout the diagram (this is where the tooling would help a lot). However, when it comes to on-chain validation of those values, only explicit conditions which are marked with ? are transformed to ErgoScript. At the same time, all other conditions are ensured off-chain during transaction building (for example in an application using Appkit API) and transaction validation when it is added to the blockchain.
7. Amount of T token
A box can store values of many tokens. The tokens on the diagram are named and a value variable may be associated with the token T using value: T expression. The value may be given by formula. If the formula is prefixed with a box name like boxName ? formula , then it is should also be checked in the guarding script of the boxName box. This additional specification is very convenient because 1) it allows to validate the visual design automatically, and 2) the conditions specified in the boxes of a diagram are enough to synthesize the necessary guarding scripts. (more about this below at “From Diagrams To ErgoScript Contracts”)
8. Tx Inputs
Inputs are connected to the corresponding transaction by orange arrows. An input arrow may have a label of the following forms:
  1. [email protected] - optional name with an index i.e. [email protected] or u/2 . This is a property of the target endpoint of the arrow. The name is used in conditions of related boxes and the index is the position of the corresponding box in the INPUTS collection of the transaction.
  2. !action - is a property of the source of the arrow and gives a name for an alternative spending path of the box (we will see this in DEX example)
Because of alternative spending paths, a box may have many outgoing orange arrows, in which case they should be labeled with different actions.
9. Transaction
A transaction spends input boxes and creates output boxes. The input boxes are given by the orange arrows and the labels are expected to put inputs at the right indexes in INPUTS collection. The output boxes are given by the green arrows. Each transaction should preserve a strict balance of ERG values (sum of inputs == sum of outputs) and for each token the sum of inputs >= the sum of outputs. The design diagram requires an explicit specification of the ERG and token values for all of the output boxes to avoid implicit errors and ensure better readability.
10. Tx Outputs
Outputs are connected to the corresponding transaction by green arrows. An output arrow may have a label of the following [email protected] , where an optional name is accompanied with an index i.e. [email protected] or u/2 . This is a property of the source endpoint of the arrow. The name is used in conditions of the related boxes and the index is the position of the corresponding box in the OUTPUTS collection of the transaction.

Example: Decentralized Exchange (DEX)

Now let's use the above described notation to design a FlowCard for a DEX dApp. It is simple enough yet also illustrates all of the key features of FlowCard diagrams which we've introduced in the previous section.
The dApp scenario is shown in the figure below: There are three participants (buyer, seller and DEX) of the DEX dApp and five different transaction types, which are created by participants. The buyer wants to swap ergAmt of ERGs for tAmt of TID tokens (or vice versa, the seller wants to sell TID tokens for ERGs, who sends the order first doesn't matter). Both the buyer and the seller can cancel their orders any time. The DEX off-chain matching service can find matching orders and create the Swap transaction to complete the exchange.
The following diagram fully (and formally) specifies all of the five transactions that must be created off-chain by the DEX dApp. It also specifies all of the spending conditions that should be verified on-chain.

https://preview.redd.it/piogz0v9ssv41.png?width=1614&format=png&auto=webp&s=e1b503a635ad3d138ef91e2f0c3b726e78958646
Let's discuss the FlowCard diagram and the logic of each transaction in details:
Buy Order Transaction
A buyer creates a Buy Order transaction. The transaction spends E amount of ERGs (which we will write E: ERG ) from one or more boxes in the pk(buyer) wallet. The transaction creates a bid box with ergAmt: ERG protected by the buyOrder script. The buyOrder script is synthesized from the specification (see below at “From Diagrams To ErgoScript Contracts”) either manually or automatically by a tool. Even though we don't need to define the buyOrder script explicitly during designing, at run time the bid box should contain the buyOrder script as the guarding proposition (which checks the box spending conditions), otherwise the conditions specified in the diagram will not be checked.
The change box is created to make the input and output sums of the transaction balanced. The transaction fee box is omitted because it can be added automatically by the tools. In practice, however, the designer can add the fee box explicitly to the a diagram. It covers the cases of more complex transactions (like Swap) where there are many ways to pay the transaction fee.
Cancel Buy, Cancel Sell Transactions
At any time, the buyer can cancel the order by sending CancelBuy transaction. The transaction should satisfy the guarding buyOrder contract which protects the bid box. As you can see on the diagram, both the Cancel and the Swap transactions can spend the bid box. When a box has spending alternatives (or spending paths) then each alternative is identified by a unique name prefixed with ! (!cancel and !swap for the bid box). Each alternative path has specific spending conditions. In our example, when the Cancel Buy transaction spends the bid box the ?buyer condition should be satisfied, which we read as “the signature for the buyer address should be presented in the transaction”. Therefore, only buyer can cancel the buy order. This “signature” condition is only required for the !cancel alternative spending path and not required for !swap .
Sell Order Transaction
The Sell Order transaction is similar to the BuyOrder in that it deals with tokens in addition to ERGs. The transaction spends E: ERG and T: TID tokens from seller's wallet (specified as pk(seller) contract). The two outputs are ask and change . The change is a standard box to balance transaction. The ask box keeps tAmt: TID tokens for the exchange and minErg: ERG - the minimum amount of ERGs required in every box.
Swap Transaction
This is a key transaction in the DEX dApp scenario. The transaction has several spending conditions on the input boxes and those conditions are included in the buyOrder and sellOrder scripts (which are verified when the transaction is added to the blockchain). However, on the diagram those conditions are not specified in the bid and ask boxes, they are instead defined in the output boxes of the transaction.
This is a convention for improved usability because most of the conditions relate to the properties of the output boxes. We could specify those properties in the bid box, but then we would have to use more complex expressions.
Let's consider the output created by the arrow labeled with [email protected] . This label tells us that the output is at the index 0 in the OUTPUTS collection of the transaction and that in the diagram we can refer to this box by the buyerOut name. Thus we can label both the box itself and the arrow to give the box a name.
The conditions shown in the buyerOut box have the form bid ? condition , which means they should be verified on-chain in order to spend the bid box. The conditions have the following meaning:
  • tAmt: TID requires the box to have tAmt amount of TID token
  • R4 == bid.id requires R4 register in the box to be equal to id of the bid box.
  • script == buyer requires the buyerOut box to have the script of the wallet where it is located on the diagram, i.e. pk(buyer)
Similar properties are added to the sellerOut box, which is specified to be at index 1 and the name is given to it using the label on the box itself, rather than on the arrow.
The Swap transaction spends two boxes bid and ask using the !swap spending path on both, however unlike !cancel the conditions on the path are not specified. This is where the bid ? and ask ? prefixes come into play. They are used so that the conditions listed in the buyerOut and sellerOut boxes are moved to the !swap spending path of the bid and ask boxes correspondingly.
If you look at the conditions of the output boxes, you will see that they exactly specify the swap of values between seller's and buyer's wallets. The buyer gets the necessary amount of TID token and seller gets the corresponding amount of ERGs. The Swap transaction is created when there are two matching boxes with buyOrder and sellOrder contracts.

From Diagrams To ErgoScript Contracts

What is interesting about FlowCard specifications is that we can use them to automatically generate the necessary ErgoTree scripts. With the appropriate tooling support this can be done automatically, but with the lack of thereof, it can be done manually. Thus, the FlowCard allows us to capture and visually represent all of the design choices and semantic details of an Ergo dApp.
What we are going to do next is to mechanically create the buyOrder contract from the information given in the DEX flow card.
Recall that each script is a proposition (boolean valued expression) which should evaluate to true to allow spending of the box. When we have many conditions to be met at the same time we can combine them in a logical formula using the AND binary operation, and if we have alternatives (not necessarily exclusive) we can put them into the OR operation.
The buyOrder box has the alternative spending paths !cancel and !swap . Thus the ErgoScript code should have OR operation with two arguments - one for each spending path.
/** buyOrder contract */ { val cancelCondition = {} val swapCondition = {} cancelCondition || swapCondition } 
The formula for the cancelCondition expression is given in the !cancel spending path of the buyOrder box. We can directly include it in the script.
/** buyOrder contract */ { val cancelCondition = { buyer } val swapCondition = {} cancelCondition || swapCondition } 
For the !swap spending path of the buyOrder box the conditions are specified in the buyerOut output box of the Swap transaction. If we simply include them in the swapCondition then we get a syntactically incorrect script.
/** buyOrder contract */ { val cancelCondition = { buyer } val swapCondition = { tAmt: TID && R4 == bid.id && @contract } cancelCondition || swapCondition } 
We can however translate the conditions from the diagram syntax to ErgoScript expressions using the following simple rules
  1. [email protected] ==> val buyerOut = OUTPUTS(0)
  2. tAmt: TID ==> tid._2 == tAmt where tid = buyerOut.tokens(TID)
  3. R4 == bid.id ==> R4 == SELF.id where R4 = buyerOut.R4[Coll[Byte]].get
  4. script == buyer ==> buyerOut.propositionBytes == buyer.propBytes
Note, in the diagram TID represents a token id, but ErgoScript doesn't have access to the tokens by the ids so we cannot write tokens.getByKey(TID) . For this reason, when the diagram is translated into ErgoScript, TID becomes a named constant of the index in tokens collection of the box. The concrete value of the constant is assigned when the BuyOrder transaction with the buyOrder box is created. The correspondence and consistency between the actual tokenId, the TID constant and the actual tokens of the buyerOut box is ensured by the off-chain application code, which is completely possible since all of the transactions are created by the application using FlowCard as a guiding specification. This may sound too complicated, but this is part of the translation from diagram specification to actual executable application code, most of which can be automated.
After the transformation we can obtain a correct script which checks all the required preconditions for spending the buyOrder box.
/** buyOrder contract */ def DEX(buyer: Addrss, seller: Address, TID: Int, ergAmt: Long, tAmt: Long) { val cancelCondition: SigmaProp = { buyer } // verify buyer's sig (ProveDlog) val swapCondition = OUTPUTS.size > 0 && { // securing OUTPUTS access val buyerOut = OUTPUTS(0) // from [email protected] buyerOut.tokens.size > TID && { // securing tokens access val tid = buyerOut.tokens(TID) val regR4 = buyerOut.R4[Coll[Byte]] regR4.isDefined && { // securing R4 access val R4 = regR4.get tid._2 == tAmt && // from tAmt: TID R4 == SELF.id && // from R4 == bid.id buyerOut.propositionBytes == buyer.propBytes // from script == buyer } } } cancelCondition || swapCondition } 
A similar script for the sellOrder box can be obtained using the same translation rules. With the help of the tooling the code of contracts can be mechanically generated from the diagram specification.

Conclusions

Declarative programming models have already won the battle against imperative programming in many application domains like Big Data, Stream Processing, Deep Learning, Databases, etc. Ergo is pioneering the declarative model of dApp development as a better and safer alternative to the now popular imperative model of smart contracts.
The concept of FlowCard shifts the focus from writing ErgoScript contracts to the overall flow of values (hence the name), in such a way, that ErgoScript can always be generated from them. You will never need to look at the ErgoScript code once the tooling is in place.
Here are the possible next steps for future work:
  1. Storage format for FlowCard Spec and the corresponding EIP standardized file format (Json/XML/Protobuf). This will allow various tools (Diagram Editor, Runtime, dApps etc) to create and use *.flowcard files.
  2. FlowCard Viewer, which can generate the diagrams from *.flowcard files.
  3. FlowCard Runtime, which can run *.flowcard files, create and send transactions to Ergo network.
  4. FlowCard Designer Tool, which can simplify development of complex diagrams . This will make designing and validation of Ergo contracts a pleasant experience, more like drawing rather than coding. In addition, the correctness of the whole dApp scenario can be verified and controlled by the tooling.
submitted by eleanorcwhite to btc [link] [comments]

FlowCards: A Declarative Framework for Development of Ergo dApps

FlowCards: A Declarative Framework for Development of Ergo dApps
Introduction
ErgoScript is the smart contract language used by the Ergo blockchain. While it has concise syntax adopted from Scala/Kotlin, it still may seem confusing at first because conceptually ErgoScript is quite different compared to conventional languages which we all know and love. This is because Ergo is a UTXO based blockchain, whereas smart contracts are traditionally associated with account based systems like Ethereum. However, Ergo's transaction model has many advantages over the account based model and with the right approach it can even be significantly easier to develop Ergo contracts than to write and debug Solidity code.
Below we will cover the key aspects of the Ergo contract model which makes it different:
Paradigm
The account model of Ethereum is imperative. This means that the typical task of sending coins from Alice to Bob requires changing the balances in storage as a series of operations. Ergo's UTXO based programming model on the other hand is declarative. ErgoScript contracts specify conditions for a transaction to be accepted by the blockchain (not changes to be made in the storage state as result of the contract execution).
Scalability
In the account model of Ethereum both storage changes and validity checks are performed on-chain during code execution. In contrast, Ergo transactions are created off-chain and only validation checks are performed on-chain thus reducing the amount of operations performed by every node on the network. In addition, due to immutability of the transaction graph, various optimization strategies are possible to improve throughput of transactions per second in the network. Light verifying nodes are also possible thus further facilitating scalability and accessibility of the network.
Shared state
The account-based model is reliant on shared mutable state which is known to lead to complex semantics (and subtle million dollar bugs) in the context of concurrent/ distributed computation. Ergo's model is based on an immutable graph of transactions. This approach, inherited from Bitcoin, plays well with the concurrent and distributed nature of blockchains and facilitates light trustless clients.
Expressive Power
Ethereum advocated execution of a turing-complete language on the blockchain. It theoretically promised unlimited potential, however in practice severe limitations came to light from excessive blockchain bloat, subtle multi-million dollar bugs, gas costs which limit contract complexity, and other such problems. Ergo on the flip side extends UTXO to enable turing-completeness while limiting the complexity of the ErgoScript language itself. The same expressive power is achieved in a different and more semantically sound way.
With the all of the above points, it should be clear that there are a lot of benefits to the model Ergo is using. In the rest of this article I will introduce you to the concept of FlowCards - a dApp developer component which allows for designing complex Ergo contracts in a declarative and visual way.
From Imperative to Declarative
In the imperative programming model of Ethereum a transaction is a sequence of operations executed by the Ethereum VM. The following Solidity function implements a transfer of tokens from sender to receiver . The transaction starts when sender calls this function on an instance of a contract and ends when the function returns.
// Sends an amount of existing coins from any caller to an address function send(address receiver, uint amount) public { require(amount <= balances[msg.sender], "Insufficient balance."); balances[msg.sender] -= amount; balances[receiver] += amount; emit Sent(msg.sender, receiver, amount); } 
The function first checks the pre-conditions, then updates the storage (i.e. balances) and finally publishes the post-condition as the Sent event. The gas which is consumed by the transaction is sent to the miner as a reward for executing this transaction.
Unlike Ethereum, a transaction in Ergo is a data structure holding a list of input coins which it spends and a list of output coins which it creates preserving the total balances of ERGs and tokens (in which Ergo is similar to Bitcoin).
Turning back to the example above, since Ergo natively supports tokens, therefore for this specific example of sending tokens we don't need to write any code in ErgoScript. Instead we need to create the ‘send’ transaction shown in the following figure, which describes the same token transfer but declaratively.
https://preview.redd.it/id5kjdgn9tv41.png?width=1348&format=png&auto=webp&s=31b937d7ad0af4afe94f4d023e8c90c97c8aed2e
The picture visually describes the following steps, which the network user needs to perform:
  1. Select unspent sender's boxes, containing in total tB >= amount of tokens and B >= txFee + minErg ERGs.
  2. Create an output target box which is protected by the receiver public key with minErg ERGs and amount of T tokens.
  3. Create one fee output protected by the minerFee contract with txFee ERGs.
  4. Create one change output protected by the sender public key, containing B - minErg - txFee ERGs and tB - amount of T tokens.
  5. Create a new transaction, sign it using the sender's secret key and send to the Ergo network.
What is important to understand here is that all of these steps are preformed off-chain (for example using Appkit Transaction API) by the user's application. Ergo network nodes don't need to repeat this transaction creation process, they only need to validate the already formed transaction. ErgoScript contracts are stored in the inputs of the transaction and check spending conditions. The node executes the contracts on-chain when the transaction is validated. The transaction is valid if all of the conditions are satisfied.
Thus, in Ethereum when we “send amount from sender to recipient” we are literally editing balances and updating the storage with a concrete set of commands. This happens on-chain and thus a new transaction is also created on-chain as the result of this process.
In Ergo (as in Bitcoin) transactions are created off-chain and the network nodes only verify them. The effects of the transaction on the blockchain state is that input coins (or Boxes in Ergo's parlance) are removed and output boxes are added to the UTXO set.
In the example above we don't use an ErgoScript contract but instead assume a signature check is used as the spending pre-condition. However in more complex application scenarios we of course need to use ErgoScript which is what we are going to discuss next.
From Changing State to Checking Context
In the send function example we first checked the pre-condition (require(amount <= balances[msg.sender],...) ) and then changed the state (i.e. update balances balances[msg.sender] -= amount ). This is typical in Ethereum transactions. Before we change anything we need to check if it is valid to do so.
In Ergo, as we discussed previously, the state (i.e. UTXO set of boxes) is changed implicitly when a valid transaction is included in a block. Thus we only need to check the pre-conditions before the transaction can be added to the block. This is what ErgoScript contracts do.
It is not possible to “change the state” in ErgoScript because it is a language to check pre-conditions for spending coins. ErgoScript is a purely functional language without side effects that operates on immutable data values. This means all the inputs, outputs and other transaction parameters available in a script are immutable. This, among other things, makes ErgoScript a very simple language that is easy to learn and safe to use. Similar to Bitcoin, each input box contains a script, which should return the true value in order to 1) allow spending of the box (i.e. removing from the UTXO set) and 2) adding the transaction to the block.
If we are being pedantic, it is therefore incorrect (strictly speaking) to think of ErgoScript as the language of Ergo contracts, because it is the language of propositions (logical predicates, formulas, etc.) which protect boxes from “illegal” spending. Unlike Bitcoin, in Ergo the whole transaction and a part of the current blockchain context is available to every script. Therefore each script may check which outputs are created by the transaction, their ERG and token amounts (we will use this capability in our example DEX contracts), current block number etc.
In ErgoScript you define the conditions of whether changes (i.e. coin spending) are allowed to happen in a given context. This is in contrast to programming the changes imperatively in the code of a contract.
While Ergo's transaction model unlocks a whole range of applications like (DEX, DeFi Apps, LETS, etc), designing contracts as pre-conditions for coin spending (or guarding scripts) directly is not intuitive. In the next sections we will consider a useful graphical notation to design contracts declaratively using FlowCard Diagrams, which is a visual representation of executable components (FlowCards).
FlowCards aim to radically simplify dApp development on the Ergo platform by providing a high-level declarative language, execution runtime, storage format and a graphical notation.
We will start with a high level of diagrams and go down to FlowCard specification.
FlowCard Diagrams
The idea behind FlowCard diagrams is based on the following observations: 1) An Ergo box is immutable and can only be spent in the transaction which uses it as an input. 2) We therefore can draw a flow of boxes through transactions, so that boxes flowing in to the transaction are spent and those flowing out are created and added to the UTXO. 3) A transaction from this perspective is simply a transformer of old boxes to the new ones preserving the balances of ERGs and tokens involved.
The following figure shows the main elements of the Ergo transaction we've already seen previously (now under the name of FlowCard Diagram).
https://preview.redd.it/9kcxl11o9tv41.png?width=1304&format=png&auto=webp&s=378a7f50769292ca94de35ff597dc1a44af56d14
There is a strictly defined meaning (semantics) behind every element of the diagram, so that the diagram is a visual representation (or a view) of the underlying executable component (called FlowCard).
The FlowCard can be used as a reusable component of an Ergo dApp to create and initiate the transaction on the Ergo blockchain. We will discuss this in the coming sections.
Now let's look at the individual pieces of the FlowCard diagram one by one.
  1. Name and Parameters
Each flow card is given a name and a list of typed parameters. This is similar to a template with parameters. In the above figure we can see the Send flow card which has five parameters. The parameters are used in the specification.
  1. Contract Wallet
This is a key element of the flow card. Every box has a guarding script. Often it is the script that checks a signature against a public key. This script is trivial in ErgoScript and is defined like the def pk(pubkey: Address) = { pubkey } template where pubkey is a parameter of the type Address . In the figure, the script template is applied to the parameter pk(sender) and thus a concrete wallet contract is obtained. Therefore pk(sender) and pk(receiver) yield different scripts and represent different wallets on the diagram, even though they use the same template.
Contract Wallet contains a set of all UTXO boxes which have a given script derived from the given script template using flow card parameters. For example, in the figure, the template is pk and parameter pubkey is substituted with the `sender’ flow card parameter.
  1. Contract
Even though a contract is a property of a box, on the diagram we group the boxes by their contracts, therefore it looks like the boxes belong to the contracts, rather than the contracts belong to the boxes. In the example, we have three instantiated contracts pk(sender) , pk(receiver) and minerFee . Note, that pk(sender) is the instantiation of the pk template with the concrete parameter sender and minerFee is the instantiation of the pre-defined contract which protects the miner reward boxes.
  1. Box name
In the diagram we can give each box a name. Besides readability of the diagram, we also use the name as a synonym of a more complex indexed access to the box in the contract. For example, change is the name of the box, which can also be used in the ErgoScript conditions instead of OUTPUTS(2) . We also use box names to associate spending conditions with the boxes.
  1. Boxes in the wallet
In the diagram, we show boxes (darker rectangles) as belonging to the contract wallets (lighter rectangles). Each such box rectangle is connected with a grey transaction rectangle by either orange or green arrows or both. An output box (with an incoming green arrow) may include many lines of text where each line specifies a condition which should be checked as part of the transaction. The first line specifies the condition on the amount of ERG which should be placed in the box. Other lines may take one of the following forms:
  1. amount: TOKEN - the box should contain the given amount of the given TOKEN
  2. R == value - the box should contain the given value of the given register R
  3. boxName ? condition - the box named boxName should check condition in its script.
We discuss these conditions in the sections below.
  1. Amount of ERGs in the box
Each box should store a minimum amount of ERGs. This is checked when the creating transaction is validated. In the diagram the amount of ERGs is always shown as the first line (e.g. B: ERG or B - minErg - txFee ). The value type ascription B: ERG is optional and may be used for readability. When the value is given as a formula, then this formula should be respected by the transaction which creates the box.
It is important to understand that variables like amount and txFee are not named properties of the boxes. They are parameters of the whole diagram and representing some amounts. Or put it another way, they are shared parameters between transactions (e.g. Sell Order and Swap transactions from DEX example below share the tAmt parameter). So the same name is tied to the same value throughout the diagram (this is where the tooling would help a lot). However, when it comes to on-chain validation of those values, only explicit conditions which are marked with ? are transformed to ErgoScript. At the same time, all other conditions are ensured off-chain during transaction building (for example in an application using Appkit API) and transaction validation when it is added to the blockchain.
  1. Amount of T token
A box can store values of many tokens. The tokens on the diagram are named and a value variable may be associated with the token T using value: T expression. The value may be given by formula. If the formula is prefixed with a box name like boxName ? formula , then it is should also be checked in the guarding script of the boxName box. This additional specification is very convenient because 1) it allows to validate the visual design automatically, and 2) the conditions specified in the boxes of a diagram are enough to synthesize the necessary guarding scripts. (more about this below at “From Diagrams To ErgoScript Contracts”)
  1. Tx Inputs
Inputs are connected to the corresponding transaction by orange arrows. An input arrow may have a label of the following forms:
  1. [email protected] - optional name with an index i.e. [email protected] or u/2 . This is a property of the target endpoint of the arrow. The name is used in conditions of related boxes and the index is the position of the corresponding box in the INPUTS collection of the transaction.
  2. !action - is a property of the source of the arrow and gives a name for an alternative spending path of the box (we will see this in DEX example)
Because of alternative spending paths, a box may have many outgoing orange arrows, in which case they should be labeled with different actions.
  1. Transaction
A transaction spends input boxes and creates output boxes. The input boxes are given by the orange arrows and the labels are expected to put inputs at the right indexes in INPUTS collection. The output boxes are given by the green arrows. Each transaction should preserve a strict balance of ERG values (sum of inputs == sum of outputs) and for each token the sum of inputs >= the sum of outputs. The design diagram requires an explicit specification of the ERG and token values for all of the output boxes to avoid implicit errors and ensure better readability.
  1. Tx Outputs
Outputs are connected to the corresponding transaction by green arrows. An output arrow may have a label of the following [email protected] , where an optional name is accompanied with an index i.e. [email protected] or u/2 . This is a property of the source endpoint of the arrow. The name is used in conditions of the related boxes and the index is the position of the corresponding box in the OUTPUTS collection of the transaction.
Example: Decentralized Exchange (DEX)
Now let's use the above described notation to design a FlowCard for a DEX dApp. It is simple enough yet also illustrates all of the key features of FlowCard diagrams which we've introduced in the previous section.
The dApp scenario is shown in the figure below: There are three participants (buyer, seller and DEX) of the DEX dApp and five different transaction types, which are created by participants. The buyer wants to swap ergAmt of ERGs for tAmt of TID tokens (or vice versa, the seller wants to sell TID tokens for ERGs, who sends the order first doesn't matter). Both the buyer and the seller can cancel their orders any time. The DEX off-chain matching service can find matching orders and create the Swap transaction to complete the exchange.
The following diagram fully (and formally) specifies all of the five transactions that must be created off-chain by the DEX dApp. It also specifies all of the spending conditions that should be verified on-chain.

https://preview.redd.it/fnt5f4qp9tv41.png?width=1614&format=png&auto=webp&s=34f145f9a6d622454906857e645def2faba057bd
Let's discuss the FlowCard diagram and the logic of each transaction in details:
Buy Order Transaction
A buyer creates a Buy Order transaction. The transaction spends E amount of ERGs (which we will write E: ERG ) from one or more boxes in the pk(buyer) wallet. The transaction creates a bid box with ergAmt: ERG protected by the buyOrder script. The buyOrder script is synthesized from the specification (see below at “From Diagrams To ErgoScript Contracts”) either manually or automatically by a tool. Even though we don't need to define the buyOrder script explicitly during designing, at run time the bid box should contain the buyOrder script as the guarding proposition (which checks the box spending conditions), otherwise the conditions specified in the diagram will not be checked.
The change box is created to make the input and output sums of the transaction balanced. The transaction fee box is omitted because it can be added automatically by the tools. In practice, however, the designer can add the fee box explicitly to the a diagram. It covers the cases of more complex transactions (like Swap) where there are many ways to pay the transaction fee.
Cancel Buy, Cancel Sell Transactions
At any time, the buyer can cancel the order by sending CancelBuy transaction. The transaction should satisfy the guarding buyOrder contract which protects the bid box. As you can see on the diagram, both the Cancel and the Swap transactions can spend the bid box. When a box has spending alternatives (or spending paths) then each alternative is identified by a unique name prefixed with ! (!cancel and !swap for the bid box). Each alternative path has specific spending conditions. In our example, when the Cancel Buy transaction spends the bid box the ?buyer condition should be satisfied, which we read as “the signature for the buyer address should be presented in the transaction”. Therefore, only buyer can cancel the buy order. This “signature” condition is only required for the !cancel alternative spending path and not required for !swap .
Sell Order Transaction
The Sell Order transaction is similar to the BuyOrder in that it deals with tokens in addition to ERGs. The transaction spends E: ERG and T: TID tokens from seller's wallet (specified as pk(seller) contract). The two outputs are ask and change . The change is a standard box to balance transaction. The ask box keeps tAmt: TID tokens for the exchange and minErg: ERG - the minimum amount of ERGs required in every box.
Swap Transaction
This is a key transaction in the DEX dApp scenario. The transaction has several spending conditions on the input boxes and those conditions are included in the buyOrder and sellOrder scripts (which are verified when the transaction is added to the blockchain). However, on the diagram those conditions are not specified in the bid and ask boxes, they are instead defined in the output boxes of the transaction.
This is a convention for improved usability because most of the conditions relate to the properties of the output boxes. We could specify those properties in the bid box, but then we would have to use more complex expressions.
Let's consider the output created by the arrow labeled with [email protected] . This label tells us that the output is at the index 0 in the OUTPUTS collection of the transaction and that in the diagram we can refer to this box by the buyerOut name. Thus we can label both the box itself and the arrow to give the box a name.
The conditions shown in the buyerOut box have the form bid ? condition , which means they should be verified on-chain in order to spend the bid box. The conditions have the following meaning:
  • tAmt: TID requires the box to have tAmt amount of TID token
  • R4 == bid.id requires R4 register in the box to be equal to id of the bid box.
  • script == buyer requires the buyerOut box to have the script of the wallet where it is located on the diagram, i.e. pk(buyer)
Similar properties are added to the sellerOut box, which is specified to be at index 1 and the name is given to it using the label on the box itself, rather than on the arrow.
The Swap transaction spends two boxes bid and ask using the !swap spending path on both, however unlike !cancel the conditions on the path are not specified. This is where the bid ? and ask ? prefixes come into play. They are used so that the conditions listed in the buyerOut and sellerOut boxes are moved to the !swap spending path of the bid and ask boxes correspondingly.
If you look at the conditions of the output boxes, you will see that they exactly specify the swap of values between seller's and buyer's wallets. The buyer gets the necessary amount of TID token and seller gets the corresponding amount of ERGs. The Swap transaction is created when there are two matching boxes with buyOrder and sellOrder contracts.
From Diagrams To ErgoScript Contracts
What is interesting about FlowCard specifications is that we can use them to automatically generate the necessary ErgoTree scripts. With the appropriate tooling support this can be done automatically, but with the lack of thereof, it can be done manually. Thus, the FlowCard allows us to capture and visually represent all of the design choices and semantic details of an Ergo dApp.
What we are going to do next is to mechanically create the buyOrder contract from the information given in the DEX flow card.
Recall that each script is a proposition (boolean valued expression) which should evaluate to true to allow spending of the box. When we have many conditions to be met at the same time we can combine them in a logical formula using the AND binary operation, and if we have alternatives (not necessarily exclusive) we can put them into the OR operation.
The buyOrder box has the alternative spending paths !cancel and !swap . Thus the ErgoScript code should have OR operation with two arguments - one for each spending path.
/** buyOrder contract */ { val cancelCondition = {} val swapCondition = {} cancelCondition || swapCondition } 
The formula for the cancelCondition expression is given in the !cancel spending path of the buyOrder box. We can directly include it in the script.
/** buyOrder contract */ { val cancelCondition = { buyer } val swapCondition = {} cancelCondition || swapCondition } 
For the !swap spending path of the buyOrder box the conditions are specified in the buyerOut output box of the Swap transaction. If we simply include them in the swapCondition then we get a syntactically incorrect script.
/** buyOrder contract */ { val cancelCondition = { buyer } val swapCondition = { tAmt: TID && R4 == bid.id && @contract } cancelCondition || swapCondition } 
We can however translate the conditions from the diagram syntax to ErgoScript expressions using the following simple rules
  1. [email protected] ==> val buyerOut = OUTPUTS(0)
  2. tAmt: TID ==> tid._2 == tAmt where tid = buyerOut.tokens(TID)
  3. R4 == bid.id ==> R4 == SELF.id where R4 = buyerOut.R4[Coll[Byte]].get
  4. script == buyer ==> buyerOut.propositionBytes == buyer.propBytes
Note, in the diagram TID represents a token id, but ErgoScript doesn't have access to the tokens by the ids so we cannot write tokens.getByKey(TID) . For this reason, when the diagram is translated into ErgoScript, TID becomes a named constant of the index in tokens collection of the box. The concrete value of the constant is assigned when the BuyOrder transaction with the buyOrder box is created. The correspondence and consistency between the actual tokenId, the TID constant and the actual tokens of the buyerOut box is ensured by the off-chain application code, which is completely possible since all of the transactions are created by the application using FlowCard as a guiding specification. This may sound too complicated, but this is part of the translation from diagram specification to actual executable application code, most of which can be automated.
After the transformation we can obtain a correct script which checks all the required preconditions for spending the buyOrder box.
/** buyOrder contract */ def DEX(buyer: Addrss, seller: Address, TID: Int, ergAmt: Long, tAmt: Long) { val cancelCondition: SigmaProp = { buyer } // verify buyer's sig (ProveDlog) val swapCondition = OUTPUTS.size > 0 && { // securing OUTPUTS access val buyerOut = OUTPUTS(0) // from [email protected] buyerOut.tokens.size > TID && { // securing tokens access val tid = buyerOut.tokens(TID) val regR4 = buyerOut.R4[Coll[Byte]] regR4.isDefined && { // securing R4 access val R4 = regR4.get tid._2 == tAmt && // from tAmt: TID R4 == SELF.id && // from R4 == bid.id buyerOut.propositionBytes == buyer.propBytes // from script == buyer } } } cancelCondition || swapCondition } 
A similar script for the sellOrder box can be obtained using the same translation rules. With the help of the tooling the code of contracts can be mechanically generated from the diagram specification.
Conclusions
Declarative programming models have already won the battle against imperative programming in many application domains like Big Data, Stream Processing, Deep Learning, Databases, etc. Ergo is pioneering the declarative model of dApp development as a better and safer alternative to the now popular imperative model of smart contracts.
The concept of FlowCard shifts the focus from writing ErgoScript contracts to the overall flow of values (hence the name), in such a way, that ErgoScript can always be generated from them. You will never need to look at the ErgoScript code once the tooling is in place.
Here are the possible next steps for future work:
  1. Storage format for FlowCard Spec and the corresponding EIP standardized file format (Json/XML/Protobuf). This will allow various tools (Diagram Editor, Runtime, dApps etc) to create and use *.flowcard files.
  2. FlowCard Viewer, which can generate the diagrams from *.flowcard files.
  3. FlowCard Runtime, which can run *.flowcard files, create and send transactions to Ergo network.
  4. FlowCard Designer Tool, which can simplify development of complex diagrams . This will make designing and validation of Ergo contracts a pleasant experience, more like drawing rather than coding. In addition, the correctness of the whole dApp scenario can be verified and controlled by the tooling.
submitted by Guilty_Pea to CryptoCurrencies [link] [comments]

[How-To] Crafting an offline TXN with the trezorlib python API

With the rollout of the new 0.12.0 API, I thought it might be time to update some of my old offline_txn scripts. The following is about 80 lines of python that will craft and sign a VERY simple transaction on Testnet.
The new rollout also comes with some new tools. The build_tx.py that is useful in conjunction with the trezorctl sign_tx command.
Both of the methods below will produce a signed TXN that can then be imported into Electrum using the "Tools -> Load transaction -> From text" command.
Note: u/Crypto-Guide has a good walkthrough for installing trezorlib in Windows if you haven't already done that.

Example of using trezorctl btc sign-tx

This example uses the build_tx.py script to build JSON to feed to the sign-tx command. You will need to download the build_tx.py file from github. It is not automatically installed with the trezor package.
```

python build_tx.py | trezorctl btc sign-tx -

Coin name [Bitcoin]: Testnet Blockbook server [btc1.trezor.io]: tbtc1.trezor.io
Previous output to spend (txid:vout) []: e294c4c172c3d87991...060fad1ed31d12ff00:0 BIP-32 path to derive the key: m/84'/1'/0'/0/0 Input amount: 129999866 Sequence Number to use (RBF opt-in enabled by default) [4294967293]: Input type (address, segwit, p2shsegwit) [segwit]:
Previous output to spend (txid:vout) []:
Output address (for non-change output) []: 2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3 Amount to spend (satoshis): 129999706
Output address (for non-change output) []: BIP-32 path (for change output) []: Transaction version [2]: Transaction locktime [0]: Please confirm action on your Trezor device.
Signed Transaction: 0200000000010100ff121dd31ead0f06...f279b642d85c48798685f86200000000 ```

Example of using crafting a TXN using trezorlib directly

If your good with python, or want to see how everything works under the hood, here's 80 lines of python to generate a similar signed transaction.
```python

!/usbin/env python3

[repo] https://github.com/brianddk/reddit ... python/offline_txn.py

[req] pip3 install trezor

from trezorlib import btc, messages as proto, tools, ui from trezorlib import MINIMUM_FIRMWARE_VERSION as min_version from trezorlib.client import TrezorClient from trezorlib.transport import get_transport from trezorlib.btc import from_json from json import loads from decimal import Decimal from sys import exit

Tested with SLIP-0014 allallall seed (slip-0014.md)

User Provided Fields; These are pulled from test scripts

CHANGE THESE!!!

coin = "Testnet"

Get legacy UTXO prev_txn hex from blockbook server. For example:

https://tbtc1.trezor.io/api/tx-specific/ \

e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00

in1_prev_txn_s = '{"txid":' \ '"e294c4c172c3d87991b0369e45d6af8584be92914d01e3060fad1ed31d12ff00"}'
in1_prev_index = 0 in1_addr_path = "m/84'/1'/0'/0/0" # allallall seed in1_amount = 129999867 out1_address = "2MsiAgG5LVDmnmJUPnYaCeQnARWGbGSVnr3" out1_amount = in1_amount - 192

Defaults

tx_version = 2 tx_locktime = 0 sequence = 4294967293

Code

in1_prev_txn_j = loads(in1_prev_txn_s, parse_float=Decimal) in1_prev_hash = in1_prev_txn_j['txid'] in1_prev_hash_b = bytes.fromhex(in1_prev_hash) device = get_transport() client = TrezorClient(transport=device, ui=ui.ClickUI())
fw_version = (client.features.major_version, client.features.minor_version, client.features.patch_version) if fw_version < min_version[client.features.model]: print("Please flash to the latest FW") exit(1)
signtx = proto.SignTx( version = tx_version, lock_time = tx_locktime )
ins = [proto.TxInputType( address_n=tools.parse_path(in1_addr_path), prev_hash=in1_prev_hash_b, prev_index=in1_prev_index, amount=in1_amount, script_type=proto.InputScriptType.SPENDWITNESS, sequence=sequence )] outs = [proto.TxOutputType( address=out1_address, amount=out1_amount, script_type=proto.OutputScriptType.PAYTOADDRESS )]
txes = None for i in ins: if i.script_type == proto.InputScriptType.SPENDADDRESS: tx = from_json(in1_prev_txn_j) txes = {in1_prev_hash_b: tx} break
_, serialized_tx = btc.sign_tx(client, coin, ins, outs, details=signtx, prev_txes=txes) client.close() print(f'{{"hex": "{serialized_tx.hex()}"}}') ```
From here, you simple take the resultant TXN hex and import it into Electrum using the "Tools -> Load transaction -> From text" clickpath
submitted by brianddk to TREZOR [link] [comments]

Groestlcoin 6th Anniversary Release

Introduction

Dear Groestlers, it goes without saying that 2020 has been a difficult time for millions of people worldwide. The groestlcoin team would like to take this opportunity to wish everyone our best to everyone coping with the direct and indirect effects of COVID-19. Let it bring out the best in us all and show that collectively, we can conquer anything.
The centralised banks and our national governments are facing unprecedented times with interest rates worldwide dropping to record lows in places. Rest assured that this can only strengthen the fundamentals of all decentralised cryptocurrencies and the vision that was seeded with Satoshi's Bitcoin whitepaper over 10 years ago. Despite everything that has been thrown at us this year, the show must go on and the team will still progress and advance to continue the momentum that we have developed over the past 6 years.
In addition to this, we'd like to remind you all that this is Groestlcoin's 6th Birthday release! In terms of price there have been some crazy highs and lows over the years (with highs of around $2.60 and lows of $0.000077!), but in terms of value– Groestlcoin just keeps getting more valuable! In these uncertain times, one thing remains clear – Groestlcoin will keep going and keep innovating regardless. On with what has been worked on and completed over the past few months.

UPDATED - Groestlcoin Core 2.18.2

This is a major release of Groestlcoin Core with many protocol level improvements and code optimizations, featuring the technical equivalent of Bitcoin v0.18.2 but with Groestlcoin-specific patches. On a general level, most of what is new is a new 'Groestlcoin-wallet' tool which is now distributed alongside Groestlcoin Core's other executables.
NOTE: The 'Account' API has been removed from this version which was typically used in some tip bots. Please ensure you check the release notes from 2.17.2 for details on replacing this functionality.

How to Upgrade?

Windows
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer.
OSX
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), run the dmg and drag Groestlcoin Core to Applications.
Ubuntu
http://groestlcoin.org/forum/index.php?topic=441.0

Other Linux

http://groestlcoin.org/forum/index.php?topic=97.0

Download

Download the Windows Installer (64 bit) here
Download the Windows Installer (32 bit) here
Download the Windows binaries (64 bit) here
Download the Windows binaries (32 bit) here
Download the OSX Installer here
Download the OSX binaries here
Download the Linux binaries (64 bit) here
Download the Linux binaries (32 bit) here
Download the ARM Linux binaries (64 bit) here
Download the ARM Linux binaries (32 bit) here

Source

ALL NEW - Groestlcoin Moonshine iOS/Android Wallet

Built with React Native, Moonshine utilizes Electrum-GRS's JSON-RPC methods to interact with the Groestlcoin network.
GRS Moonshine's intended use is as a hot wallet. Meaning, your keys are only as safe as the device you install this wallet on. As with any hot wallet, please ensure that you keep only a small, responsible amount of Groestlcoin on it at any given time.

Features

Download

iOS
Android

Source

ALL NEW! – HODL GRS Android Wallet

HODL GRS connects directly to the Groestlcoin network using SPV mode and doesn't rely on servers that can be hacked or disabled.
HODL GRS utilizes AES hardware encryption, app sandboxing, and the latest security features to protect users from malware, browser security holes, and even physical theft. Private keys are stored only in the secure enclave of the user's phone, inaccessible to anyone other than the user.
Simplicity and ease-of-use is the core design principle of HODL GRS. A simple recovery phrase (which we call a Backup Recovery Key) is all that is needed to restore the user's wallet if they ever lose or replace their device. HODL GRS is deterministic, which means the user's balance and transaction history can be recovered just from the backup recovery key.

Features

Download

Main Release (Main Net)
Testnet Release

Source

ALL NEW! – GroestlcoinSeed Savior

Groestlcoin Seed Savior is a tool for recovering BIP39 seed phrases.
This tool is meant to help users with recovering a slightly incorrect Groestlcoin mnemonic phrase (AKA backup or seed). You can enter an existing BIP39 mnemonic and get derived addresses in various formats.
To find out if one of the suggested addresses is the right one, you can click on the suggested address to check the address' transaction history on a block explorer.

Features

Live Version (Not Recommended)

https://www.groestlcoin.org/recovery/

Download

https://github.com/Groestlcoin/mnemonic-recovery/archive/master.zip

Source

ALL NEW! – Vanity Search Vanity Address Generator

NOTE: NVidia GPU or any CPU only. AMD graphics cards will not work with this address generator.
VanitySearch is a command-line Segwit-capable vanity Groestlcoin address generator. Add unique flair when you tell people to send Groestlcoin. Alternatively, VanitySearch can be used to generate random addresses offline.
If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then VanitySearch is the right choice for you to create a more personalized address.
VanitySearch is a groestlcoin address prefix finder. If you want to generate safe private keys, use the -s option to enter your passphrase which will be used for generating a base key as for BIP38 standard (VanitySearch.exe -s "My PassPhrase" FXPref). You can also use VanitySearch.exe -ps "My PassPhrase" which will add a crypto secure seed to your passphrase.
VanitySearch may not compute a good grid size for your GPU, so try different values using -g option in order to get the best performances. If you want to use GPUs and CPUs together, you may have best performances by keeping one CPU core for handling GPU(s)/CPU exchanges (use -t option to set the number of CPU threads).

Features

Usage

https://github.com/Groestlcoin/VanitySearch#usage

Download

Source

ALL NEW! – Groestlcoin EasyVanity 2020

Groestlcoin EasyVanity 2020 is a windows app built from the ground-up and makes it easier than ever before to create your very own bespoke bech32 address(es) when whilst not connected to the internet.
If you're tired of the random, cryptic bech32 addresses generated by regular Groestlcoin clients, then Groestlcoin EasyVanity2020 is the right choice for you to create a more personalised bech32 address. This 2020 version uses the new VanitySearch to generate not only legacy addresses (F prefix) but also Bech32 addresses (grs1 prefix).

Features

Download

Source

Remastered! – Groestlcoin WPF Desktop Wallet (v2.19.0.18)

Groestlcoin WPF is an alternative full node client with optional lightweight 'thin-client' mode based on WPF. Windows Presentation Foundation (WPF) is one of Microsoft's latest approaches to a GUI framework, used with the .NET framework. Its main advantages over the original Groestlcoin client include support for exporting blockchain.dat and including a lite wallet mode.
This wallet was previously deprecated but has been brought back to life with modern standards.

Features

Remastered Improvements

Download

Source

ALL NEW! – BIP39 Key Tool

Groestlcoin BIP39 Key Tool is a GUI interface for generating Groestlcoin public and private keys. It is a standalone tool which can be used offline.

Features

Download

Windows
Linux :
 pip3 install -r requirements.txt python3 bip39\_gui.py 

Source

ALL NEW! – Electrum Personal Server

Groestlcoin Electrum Personal Server aims to make using Electrum Groestlcoin wallet more secure and more private. It makes it easy to connect your Electrum-GRS wallet to your own full node.
It is an implementation of the Electrum-grs server protocol which fulfils the specific need of using the Electrum-grs wallet backed by a full node, but without the heavyweight server backend, for a single user. It allows the user to benefit from all Groestlcoin Core's resource-saving features like pruning, blocks only and disabled txindex. All Electrum-GRS's feature-richness like hardware wallet integration, multi-signature wallets, offline signing, seed recovery phrases, coin control and so on can still be used, but connected only to the user's own full node.
Full node wallets are important in Groestlcoin because they are a big part of what makes the system be trust-less. No longer do people have to trust a financial institution like a bank or PayPal, they can run software on their own computers. If Groestlcoin is digital gold, then a full node wallet is your own personal goldsmith who checks for you that received payments are genuine.
Full node wallets are also important for privacy. Using Electrum-GRS under default configuration requires it to send (hashes of) all your Groestlcoin addresses to some server. That server can then easily spy on your transactions. Full node wallets like Groestlcoin Electrum Personal Server would download the entire blockchain and scan it for the user's own addresses, and therefore don't reveal to anyone else which Groestlcoin addresses they are interested in.
Groestlcoin Electrum Personal Server can also broadcast transactions through Tor which improves privacy by resisting traffic analysis for broadcasted transactions which can link the IP address of the user to the transaction. If enabled this would happen transparently whenever the user simply clicks "Send" on a transaction in Electrum-grs wallet.
Note: Currently Groestlcoin Electrum Personal Server can only accept one connection at a time.

Features

Download

Windows
Linux / OSX (Instructions)

Source

UPDATED – Android Wallet 7.38.1 - Main Net + Test Net

The app allows you to send and receive Groestlcoin on your device using QR codes and URI links.
When using this app, please back up your wallet and email them to yourself! This will save your wallet in a password protected file. Then your coins can be retrieved even if you lose your phone.

Changes

Download

Main Net
Main Net (FDroid)
Test Net

Source

UPDATED – Groestlcoin Sentinel 3.5.06 (Android)

Groestlcoin Sentinel is a great solution for anyone who wants the convenience and utility of a hot wallet for receiving payments directly into their cold storage (or hardware wallets).
Sentinel accepts XPUB's, YPUB'S, ZPUB's and individual Groestlcoin address. Once added you will be able to view balances, view transactions, and (in the case of XPUB's, YPUB's and ZPUB's) deterministically generate addresses for that wallet.
Groestlcoin Sentinel is a fork of Groestlcoin Samourai Wallet with all spending and transaction building code removed.

Changes

Download

Source

UPDATED – P2Pool Test Net

Changes

Download

Pre-Hosted Testnet P2Pool is available via http://testp2pool.groestlcoin.org:21330/static/

Source

submitted by Yokomoko_Saleen to groestlcoin [link] [comments]

Contrats d'exécution consensuels de VDS et processus du téléchargement à la chaîne

Résumé des contrats d’exécution consensuels
Le concept de base du contrat d’exécution consensuels
Contrats d’exécution consensuels, connu sous le nom de contrat intelligent dans l'industrie de la blockchain, mais l'équipe de VDS estime que ce terme est trop marketing, car nous n'avons pas trouvé à quel point la technologie de programmation contractuelle est intelligente jusqu'à présent, il s'agit simplement d'un système décentralisé dans le réseau distribué, la procédure prédéfinie de comportement consensuel formée par l'édition de code. Dans l'esprit de rechercher la vérité à partir des faits, nous pensons qu'il est plus approprié de renommer le contrat intelligent en tant que contrat d'exécution de consensus. Lorsque les humains combineront la technologie blockchain avec la technologie d'intelligence artificielle de AI à l'avenir, les obstacles à la compréhension des noms sont éliminés.
Le contrat d'exécution consensuel peut être appliqué à de nombreuses industries, telles que la finance, l'éducation, les systèmes administratifs, l'Internet des objets, le divertissement en ligne, etc. Grâce à la technologie de la blockchain, dans un réseau distribué spécifique, un script d'exécution qui est formé par l'édition de pré-code sans aucune intervention de tiers et le comportement de consensus des deux parties ou de plusieurs parties impliquées dans le protocole. Il garantit l’exécution sûre, stable et équitable des droits et intérêts de tous les participants au contrat.
Le contrat d'exécution consensuel a joué un rôle dans l'accélération de l'atterrissage de diverses applications pour le développement de l'industrie de la blockchain et a incité davantage de développeurs à y participer activement, révolutionnant l'expérience réelle des produits de la technologie de la blockchain. Tout découle des contributions exceptionnelles de l'équipe Ethereum, ouvrant une nouvelle porte à l'ensemble de l'industrie.
Structure de base et jonction
L’intégration de EVM
La machine virtuelle Ethereum (EVM) utilise un code machine 256 bits et est une machine virtuelle basée sur la pile utilisée pour exécuter les contrats d'exécution consensuels d'Ethereum. Étant donné que l'EVM est conçu pour le système Ethereum, le modèle de compte Ethereum (Account Model) est utilisé pour la transmission de valeurs. La conception de la chaîne VDS est basée sur le modèle Bitcoin UTXO. La raison de cette conception est, d'une part, c'est en raison de la nécessité de réaliser la fonction d'échange de résonance de VDS et la fonction d'échange inter-chaîne unidirectionnelle de bitcoin à chaîne VDS, qui peuvent réaliser la génération de deux adresses différentes de bitcoin et VDS avec une clé privée. D'autre part, l'équipe VDS estime que la structure sous-jacente des transactions Bitcoin est plus stable et fiable grâce à 10 ans de pratique sociale. Par conséquent, VDS utilise une couche d'abstraction de compte (Account Abstraction Layer) pour convertir le modèle UTXO en un modèle de compte qui peut être exécuté par EVM. De plus, VDS a ajouté une interface basée sur le modèle de compte, afin qu'EVM puisse lire directement les informations sur la chaîne VDS. Il convient de noter que la couche d'abstraction de compte peut masquer les détails de déploiement de certaines fonctions spécifiques et établir une division des préoccupations pour améliorer l'interopérabilité et l'indépendance de la plate-forme.
Dans le système Bitcoin, ce n'est qu'après la vérification du script de déverrouillage (Script Sig) et du script de verrouillage (Script Pub Key) que la sortie de transaction correspondante peut être dépensée.
Par exemple, le script de verrouillage verrouille généralement une sortie de transaction sur une adresse bitcoin (la valeur de hachage de la clé publique). Ce n'est que lorsque les conditions de configuration du script de déverrouillage et du script de verrouillage correspondent, que l'exécution du script combiné affiche le résultat sous la forme True (la valeur de retour de système est 1), de sorte que la sortie de transaction correspondante sera dépensée.
Dans le système distribué de VDS, nous soulignons l'opportunité de l'exécution du contrat d'exécution consensuel. Par conséquent, nous avons ajouté les opérateurs OP_CREATE et OP_CALL au script de verrouillage. Lorsque le système de VDS détecte cet opérateur, les nœuds de l'ensemble du réseau exécuteront la transaction. De cette façon, le rôle joué par le script Bitcoin est plus de transférer les données pertinentes vers EVM, pas seulement en tant que langage de codage. Tout comme Ethereum exécute un contrat d'exécution de consensus, le contrat déclenché par les opérateurs OP_CREATE et OP_CALL, EVM changera son état dans sa propre base de données d'état.
Compte tenu de la facilité d'utilisation du contrat d'exécution du consensus de la chaîne VDS, il est nécessaire de vérifier les données qui déclenchent le contrat et la valeur de hachage de la clé publique de la source de données.
Afin d'éviter que la proportion d'UTXO sur la chaîne de VDS ne soit trop importante, la sortie de transaction de OP_CREATE et OP_CALL est t conçue pour être dépensée. La sortie de OP_CALL peut envoyer des fonds pour d'autres contrats ou adresses de hachage de clé publique.
Tout d’abord, pour le contrat d'exécution consensuel créé sur la chaîne VDS, le système généreraune valeur de hachage de transaction pour l'appel de contrat.Le contrat nouvellement libéré a un solde initial de 0 (les contrats avec un solde initial ne sont pas 0 ne sont pas pris en charge). Afin de répondre aux besoins du contrat d'envoi de fonds, VDS utilise l'opérateur OP_CALL pour créer une sortie de transaction. Le script de sortie du contrat d'envoi de fonds est similaire à :
1: the version of the VM
10000: gas limit for the transaction
100: gas price in Qtum satoshis
0xF012: data to send to the contract (usually using the solidity ABI)
0x1452b22265803b201ac1f8bb25840cb70afe3303:
ripemd-160 hash of the contract txid OP_CALL
Ce script n'est pas compliqué et OP_CALL effectue la plupart du travail requis. VDS définit le coût spécifique de la transaction (sans tenir compte de la situation de out-of-gas) comme Output Value, qui est Gas Limit. Le mécanisme spécifique du Gas sera discuté dans les chapitres suivants. Lorsque le script de sortie ci-dessus est ajouté à la blockchain, la sortie établit une relation correspondante avec le compte du contrat et se reflète dans le solde du contrat. Le solde peut être compris comme la somme des coûts contractuels disponibles.
La sortie d'adresse de hachage de clé publique standard est utilisée pour le processus de base des transactions de contrat, et le processus de transaction entre les contrats est également généralement cohérent. En outre, vous pouvez effectuer des transactions par P2SH et des transactions non standard (non-standard transactions). Lorsque le contrat actuel doit être échangé avec un autre contrat ou une adresse de hachage de clé publique, la sortie disponible dans le compte du contrat sera consommée. Cette partie de la sortie consommée doit être présente pour la vérification des transactions dans le réseau de VDS, que nous appelons la transaction attendue du contrat (Expected Contract Transactions). Étant donné que la transaction attendue du contrat est générée lorsque le mineur vérifie et exécute la transaction, plutôt que d'être générée par l'utilisateur de la transaction, elle ne sera pas diffusée sur l'ensemble du réseau.
Le principe de fonctionnement principal de la transaction attendue du contrat est réalisé par le code OP_SPEND. OP_CREATE et OP_CALL ont deux modes de fonctionnement. Lorsque l'opérateur est utilisé comme script de sortie, EVM l'exécute, lorsque l'opérateur est utilisé comme script d'entrée, EVM ne sera pas exécuté (sinon il provoquera une exécution répétée). Dans ce cas, OP_CREATE et OP_CALL peuvent être utilisés comme Opération sans commandement. OP_CREATE et OP_CALL reçoivent la valeur de hachage de transaction transmise par OP_SPEND et renvoient 1 ou 0 (c'est-à-dire il peut être dépensé ou pas). Il montre l'importance de OP_SPEND dans la transaction attendue de l'intégralité du contrat. Plus précisément, lorsque OP_SPEND transmet la valeur de hachage de transaction à OP_CREATE et OP_CALL, OP_CREATE et OP_CALL comparent si la valeur de hachage existe dans la liste des transactions attendues du contrat. S'il existe, renvoyez 1 pour dépenser, sinon retournez 0, ce n'est pas pour dépenser. Cette logique fournit indirectement un moyen complet et sûr de garantir que les fonds du contrat ne peuvent être utilisés que par le contrat, ce qui est cohérent avec le résultat des transactions UTXO ordinaires.
Lorsque le contrat EVM envoie des fonds à l'adresse de hachage de clé publique ou à un autre contrat, une nouvelle transaction sera établie. À l'aide de l'algorithme de Consensus-critical coin picking, la sortie de transaction la plus appropriée peut être sélectionnée dans le pool de sortie disponible du contrat. La sortie de transaction sélectionnée sera utilisée comme script d'entrée pour exécuter un seul OP_SPEND, et la sortie est l'adresse cible des fonds, et les fonds restants seront renvoyés au contrat, tout en modifiant la sortie disponible pour la consommation. Ensuite, la valeur de hachage de cette transaction sera ajoutée à la liste des transactions attendues du contrat. Lorsque la transaction est exécutée, la transaction sera immédiatement ajoutée au bloc. Une fois que les mineurs de la chaîne ont vérifié et exécuté la transaction, la liste des transactions attendues du contrat est à nouveau parcourue. Une fois la vérification correcte, la valeur de hachage est supprimée de la table. De cette façon, l'utilisation de OP_SPEND peut effectivement empêcher l'utilisation de valeurs de hachage codées en dur pour modifier le coût de la sortie.
La couche d'abstraction des comptes VDS élimine la nécessité pour l'EVM d'accorder trop d'attention à coin-picking. Il lui suffit de connaître le solde du contrat et peut échanger des fonds avec d'autres contrats ou même des adresses de hachage de clé publique. De cette façon, seule une légère modification du contrat d'exécution du consensus Ethereum peut répondre aux exigences de fonctionnement du contrat VDS.
En d'autres termes, tant que le contrat d'exécution consensuel peut être exécuté sur la chaîne Ethereum, il peut s'exécuter sur la chaîne VDS.
Achèvement de AAL
La conception de la chaîne VDS est basée sur le modèle Bitcoin UTXO. La plate-forme générale de contrat d'exécution de consensus utilise le modèle de compte. Étant donné que le contrat en tant qu'entité nécessite un logo de réseau, ce logoest l'adresse du contrat, de sorte que le fonctionnement et la gestion du contrat d'exécution consensuel peuvent être effectués par cette adresse. La couche d'abstraction de compte est ajoutée à la conception du modèle (Account Abstraction Layer, AAL) de chaîne de VDS, qui est utilisée pour convertir le modèle UTXO en un modèle de compte qui peut être exécuté par le contrat.
Pour les développeurs qui exécutent des contrats par consensus, le modèle de compte de la machine virtuelle est relativement simple. Il prend en charge l'interrogation des soldes des contrats et peut également envoyer des fonds pour d'autres contrats. Bien que ces opérations semblent très simples et basiques, toutes les transactions de la chaîne VDS utilisent le langage de script Bitcoin, et il est plus compliqué que prévu d'être implémenté dans la couche d'abstraction de compte de la chaîne VDS basée sur le modèle Bitcoin UTXO. AAL a donc élargi sa base en ajoutant trois nouveaux opérateurs :
OP_CREATE est utilisé pour effectuer la création de contrats intelligents, transmettre le code d'octet transmis via la transaction à la base de données de stockage de contrats de la machine virtuelle et générer un compte de contrat.
OP_CALL est utilisé pour transférer les données pertinentes et les informations d'adresse nécessaires pour appeler le contrat et exécuter le contenu du code dans le contrat. (Cet opérateur peut également envoyer des fonds pour des contrats d'exécution consensuels).
OP_SPEND utilise la valeur de hachage de ID de contrat actuel comme transaction d'entrée HASH ou transaction HASH envoyée à l'UTXO du contrat, puis utilise OP_SPEND comme instruction de dépense pour créer un script de transaction.
Utilisation des Contrats et processus du téléchargement à la chaîne
Rédiger les contrats
Il est actuellement possible d'utiliser le langage Solidity pour rédiger des contrats d'exécution de consensus.
Utilisez Solidity Remix ou un autre Solidity IDE pour l'écriture et la compilation de code.
solidity remix(https://remix.ethereum.org/
Il est recommandé d'utiliser le mode homestead pour compiler.
Il est recommandé d'utiliser la version solidité 0.4.24 (si d'autres versions sont utilisées, cela peut provoquer des erreurs ou des échecs).
La syntaxe Solidity peut être référencée(https://solidity.readthedocs.io/en)
Compiler et déployer les contrats
Fonctionnement du contrat intelligent de vdsd
Examiner les variables de fonctionnement de l'environnement
vdsd -txindex=1 -logevents=1 -record-log-opcodes=1 -regtest=1
> Les tests sous contrat sont effectués dans l'environnement de test. Il est recommandé de tester après avoir atteint une hauteur de 440 blocs.
440 blocs hautement achevés l'opération de retour de fonds après les événements anormaux du contrat (refund) et (revert).
La commande de contrat de déploiement est :
```vds-cli deploycontract bytecode ABI parameters```
- bytecode (string, required) contract bytecode.
- ABI (string, required) ABI String must be JSON formatted.
- parameters (string, required) a JSON array of parameters.
Cette fonction est utilisée pour l'exécution du constructeur du contrat avec les paramètres entrants pour obtenir le ByteCode qui est finalement utilisé pour le déploiement.
(Cette méthode consiste à associer le bytecode à ABI et à le stocker localement pour l'enregistrement. Il peut appeler des méthodes internes localement et renvoyer le bytecode approprié)
```vds-cli createcontract bytecode (gaslimit gasprice senderaddress broadcast)```
- bytecode (string, required) contract bytecode.
- gaslimit (numeric or string, optional) gasLimit, default is DEFAULT_GAS_LIMIT, recommended value is 250000.
- gasprice (numeric or string, optional) gasprice, default is DEFAULT_GAS_PRICE, recommended value is 0.00000040.
- senderaddress (string, optional) The vds address that will be used to create the contract.
- broadcast (bool, optional, default=true) Whether to broadcast the transaction or not.
- changeToSender (bool, optional, default=true) Return the change to the sender.
La valeur de retour est : txid, éxpéditeur, hachage de l'expéditeur160, adresse du contrat
Consulter si la commande a été exécutée avec succès :
```vds-cli gettransactionreceipt txid```
La valeur de retour de txid pour les transactions non contractuelles est vide
La valeur de retour est : Les informations pertinentes de txid sur la BlockHash Hachage du bloc
- blockNumber Hauteur de bloc
- transactionHash Hachage de transaction
- transactionIndex La position de l'échange dans le bloc
- from Hachage de l’adresse de l’expéditeur 160
- to Le destinataire est l'adresse du contrat, le lieu de création de la transaction contractuelle est 00000000000000000000000000000
- cumulativeGasUsed Gas accumulé
- gasUsed Gaz réellement utilisé
- contractAddress Adresse du contrat
- excepted Y a-t-il des erreurs
- exceptedMessage Message d'erreur
-
Il convient de noter que le champ excepted n'est pas None, ce qui indique que l'exécution du contrat a échoué. Bien que la transaction puisse être vérifiée sur la chaîne, cela ne signifie pas que le contrat a été exécuté avec succès, c'est-à-dire que les frais de traitement pour l'exécution de ce contrat ne sont pas remboursables. Les frais de traitement ne seront remboursés que si la méthode revert est entrée dans le contrat, et les frais de méthode ne seront pas remboursés pour la méthode assert.
Appel des contrats
```vds-cli addcontract name contractaddress ABI decription```
- name (string required) contract name.
- contractaddress (string required) contract address.
- ABI (string, required) ABI String must be JSON formatted.
- description (string, optional) The description to this contract.
Cette fonction est utilisée pour ajouter le contrat ABI à la base de données locale.
```vds-cli getcontractinfo contractaddress```
- contractaddress (string required) contract address.
Cette fonction est utilisée pour obtenir les informations du contrat ajouté.
```vds-cli callcontractfunc contractaddress function parameters```
- contractaddress (string, required) The contract address that will receive the funds and data.
- function (string, required) The contract function.
- parameters (string, required) a JSON array of parameters.
Cette fonction renverra le résultat de l'exécution lors de l'appel de la méthode constante ordinaire, comme l'appel de la méthode d'opération de données de contrat retournera la chaîne de format hexadécimal du script d'opération.
```vds-cli sendtocontract contractaddress data (amount gaslimit gasprice senderaddress broadcast)```
- contractaddress (string, required) The contract address that will receive the funds and data.
- datahex (string, required) data to send.
- amount (numeric or string, optional) The amount in " + CURRENCY_UNIT + " to send. eg 0.1, default: 0
- gaslimit (numeric or string, optional) gasLimit, default is DEFAULT_GAS_LIMIT, recommended value is 250000.
- gasprice (numeric or string, optional) gasprice, default is DEFAULT_GAS_PRICE, recommended value is 0.00000040.
- senderaddress (string, optional) The vds address that will be used to create the contract.
- broadcast (bool, optional, default=true) Whether to broadcast the transaction or not.
- changeToSender (bool, optional, default=true) Return the change to the sender.
Cette fonction est utilisée pour envoyer le script d'opération de contrat au contrat spécifié et le faire enregistrer sur la blockchain.
Consultation des résultats d’exécution des contrats
```vds-cli gettransaction txid```
Cette commande est utilisée pour afficher les heures de confirmation de la transaction de portefeuille actuelle.
```vds-cli gettransactionreceipt txid```
Cette commande est utilisée pour vérifier les résultats d'exécution de la création de contrat et des transactions d'appel, s'il y a des exceptions levées et des consommations réelles de GAS.
`${datadir}/vmExecLogs.json` enregistrera les appels de contrat sur la blockchain. Ce fichier servira d'interface externe pour les événements de contrat.
Interface d'appel des contrats
l Interface de création de contrat createcontract
l Interface de déploiement de contrat deploycontract
l Interface d'ajout ABI addcontract
l Interface d’appel des contrats avec l’opération des fons sendtocontract
l Interface de lecture des informations sur les contrats callcontractfunc
l Interface d'acquisition d'informations sur l'exécution des transactions contractuelles gettransactionreceipt
L’expliquation des coûts d’expoitation des contrats
Les coûts de fonctionnement de la création d'un contrat sont toutes des méthodes estimées, et un succès d'exécution à 100% ne peut pas être garanti, car gas limit a une limite supérieure de 50000000, et les contrats dépassant cette limite entraîneront un échec. La chaîne de VDS utilise une méthode de rendre la monnaie, ce qui signifie que même si beaucoup de gaz est envoyé, le mineur n'utilisera pas tout le gas et restituera le gas restant. Alors ne vous inquiétez pas de dépenser trop de gas.
Le coût de création d'un contrat est approximativement de la taille du Byte Code * 300 comme gas limit, le gas price minimum est de 0.0000004, gas price * gas limit est le coût de création d'un contrat.
En ce qui concerne l'exécution de la méthode dans un contrat, le gas requis est estimé. En raison de la congestion du réseau, l'estimation ne garantit pas que 100% peuvent être téléchargés avec succès dans la chaîne. Par conséquent, je crains de tromper et de demander au développeur de vérifier les résultats.
submitted by YvanMay to u/YvanMay [link] [comments]

Bitcoin JSON-RPC Tutorial 2 - VPS Setup Bitcoin JSON-RPC Tutorials - YouTube Learning Bitcoin 4 - Bitcoin Command Line Helper - Part 1

The second method uses JSON-RPC. This is a common interface that allows you to connect to bitcoind and execute commands from any language - and possibly even from another computer. The Bitcoin Wiki has a page with a detailed description of some ways to make a JSON-RPC call in various programming languages. For brevity, only two are listed. In ... There are two variations of the original bitcoin program available; one with a graphical user interface (usually referred to as just “Bitcoin”), and a 'headless' version (called bitcoind).They are completely compatible with each other, and take the same command-line arguments, read the same configuration file, and read and write the same data files. Each key is a bitcoin address or hex-encoded public key. If [account] is specified, assign address to [account]. Returns a string containing the address. N addnode <node> <add/remove/onetry> version 0.8 Attempts add or remove <node> from the addnode list or try a connection to <node> once. N backupwallet <destination> Safely copies wallet.dat to destination, which can be a directory or a path ... # JSON-RPC options (for controlling a running Bitcoin/bitcoind process) # # server=1 tells Bitcoin-Qt and bitcoind to accept JSON-RPC commands: #server=0 # Bind to given address to listen for JSON-RPC connections. # Refer to the manpage or bitcoind -help for further details. #rpcbind=<addr> # If no rpcpassword is set, rpc cookie auth is sought ... A list of some frequently needed Litecoin commands for my reference (for use with litecoin-cli on Linux). Table Of Contents Litecoin CLI Commands The JSON RPC API JSON RPC Headers You can get started with the JSON RPC API using the Authorization and Content-Type headers, similar to the ones shown below. The request method is […]

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Bitcoin JSON-RPC Tutorial 2 - VPS Setup

Bitcoin JSON-RPC Tutorial 4 - Command Line Interface - Duration: 5:14. m1xolyd1an 10,467 views. 5:14. AWS - Bitcoin Full Node Setup - Duration: 7:46. Blockchain Explained 505 views. 7:46 . Bitcoin ... Skip navigation Sign in. Search Bitcoin JSON-RPC Tutorial 4 - Command Line Interface - Duration: 5:14. m1xolyd1an 10,127 views. 5:14. Language: English Location: United States Restricted Mode: Off History Help ... Bitcoin JSON-RPC Tutorial 4 - Command Line Interface - Duration: 5:14. m1xolyd1an Recommended for you. 5:14. Bitcoin Lightning Network Tutorial Part 1 - Setup Bitcoind - Duration: 15:10.

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