Exploring the bitcoindevkit CLI part 2

Feb 2021

bitcoin , bitcoindevkit

Example Wallet

The examples below make use of the following testnet BIP84 wallet:

damage urban exercise recipe company execute ship damage offer point cereal exclude

Using the restore command, we find that the xprv for the wallet is

tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF

This means the descriptor for a BIP84 bitcoin testnet, account 0, series of receive addresses is:

wpkh(tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF/84'/1'/0'/0/*)

Generating New Keys

Generate a new extended master key suitable for using in a descriptor with

bdk-cli key generate --entropy 12
{
  "fingerprint": "2a0e129d",
  "mnemonic": "vocal fantasy gap lumber guess broom gate creek game coral rice flock",
  "xprv": "tprv8ZgxMBicQKsPedUmFPeHeJWa1C4rQFpUZzwU1QhgSCoZtzqFACQXT5Li8NQLRH1syNVi3iZi5PUUGkTDGXV1CUpeusLxf77Xzm969Ur8uy5",
  "xpub": "tpubD6NzVbkrYhZ4Y6WZ93Jt3iAgaDanZb1P9JYFHvjyrUbxjV61nbE7dZxaJYHYK29MrpLJKc7uKo1gTUhTHni21sgh4mT5p2Qs6pRXoXFFWzY"
}

This xprv master key can then be used to derive common BIP 39/44/84 wallets. For example the BIP84 receive and change wallet descriptors would be the following:

# receive wallet
wpkh(tprv8ZgxMBicQKsPedUmFPeHeJWa1C4rQFpUZzwU1QhgSCoZtzqFACQXT5Li8NQLRH1syNVi3iZi5PUUGkTDGXV1CUpeusLxf77Xzm969Ur8uy5/84'/1'/0'/0/*)  

# change wallet
wpkh(tprv8ZgxMBicQKsPedUmFPeHeJWa1C4rQFpUZzwU1QhgSCoZtzqFACQXT5Li8NQLRH1syNVi3iZi5PUUGkTDGXV1CUpeusLxf77Xzm969Ur8uy5/84'/1'/0'/1/*)

You can restore keys from a mnemonic using the restore subcommand:

bdk-cli key restore --mnemonic "vocal fantasy gap lumber guess broom gate creek game coral rice flock"

Creating and Syncing a Wallet

All wallet operations use the wallet subcommand. You sync your wallet to the blockchain with the appropriately named sync subcommand:

bdk-cli wallet --descriptor "wpkh(tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF/84'/1'/0'/0/*)" sync

When we give bdk-cli a descriptor, it creates a entry for us in a small sled database located at ~/.bdk-bitcoin/ on our machine. This wallet does not actually contain the descriptor (hence the need to provide it at every command) but does keep track of a few things for you that make it convenient. Note that you can delete this database at any time without loosing anything that cannot be rebuilt by syncing back up.

This sort of “cache” has a default name of main, and if you try and give bdk a new command but with a different descriptor (say you want to test with multiple wallets at once), it will throw an error, since the new descriptor will not match the currently existing ‘main’ wallet in the database.

The way to play with multiple wallets at once is to name them as they are being created and used. The command above could be modified like so:

bdk-cli wallet --wallet "testwalletnumber1" --descriptor "wpkh(tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF/84'/1'/0'/0/*)" sync

which will create a wallet called testwalletnumber1 in the database. If you are dealing with multiple wallets, you must provide the --wallet option every time, unless you wish to use the default wallet.

Receiving coins

bdk-cli wallet --wallet bdk-by-example --descriptor "wpkh(tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF/84'/1'/0'/0/*)" repl  

>> get_new_address
{
  "address": "tb1qa9tay78q3hc6470e4f7v3pmqukzrauvgcl7qjt"
}

>> list_transactions
[
  {
    "fees": 141,
    "height": null,
    "received": 10000,
    "sent": 0,
    "timestamp": 0,
    "transaction": null,
    "txid": "2b74aa4a0775162051f51d960ecc1b7e623d3d57d18fcfca7ea4d0e642f89918"
  }
]

Sending coins

A simple send transaction is done using the following steps:

Create the transaction (create_tx --to "<address:sat>")
Sign the psbt (sign --psbt <psbt from step 1>)
Broadcast the transaction (broadcast --psbt <signed psbt from step 2>)

The create_tx subcommand requires the --to flag with an argument in the format address:sat.

The example below performs that transaction using the repl. Note that when providing the psbts to the repl we do not enclose the psbt in quotation marks, whereas if we perform these commands using the normal cli we do need to put the psbts in quotes.

bdk-cli repl --wallet bdk-by-example --descriptor "wpkh(tprv8ZgxMBicQKsPdTayefG3Up8B1Rq3AwqQDfvEjt6oJCCwse3s79er2hYn8erb4rTgddL55SGKa8TjkoytzZXc7Kj4BLZwu2rzCFbE1KMfQtF/84'/1'/0'/0/*)"

>> create_tx --to "tb1qjpfm4vz5w2l0hzp2t0fd8esguxe08pntgv79vl:3232"
{
  "details": {
    "fees": 141,
    "height": null,
    "received": 3042,
    "sent": 6415,
    "timestamp": 1611499836,
    "transaction": null,
    "txid": "f6ef8179b7612a272205bd152d8e833b6b9ced11aedbb2678eb9ba211157bb12"
  },
  "psbt": "cHNidP8BAHEBAAAAARAnt7YyE0GznP/9ddMvJj21UZJvYxePoPZzLKQaABqrAQAAAAD/////AuILAAAAAAAAFgAUR/J8qBUWz+VI4IPMZf9h4V2LbWmgDAAAAAAAABYAFJBTurBUcr77iCpb0tPmCOGy84ZrAAAAAAABAR8PGQAAAAAAABYAFEVWZq4wmchQmMHuTxXn5nJorLFiIgYD2buG/D7EDLZn7nsbD8JEpdDrJ//odPM1S6dLbxhwv7sY1n+6l1QAAIABAACAAAAAgAAAAAACAAAAACICA8EuowXeoqVzny4kvL5RrEiNBBDrKGQaXv7yEq+2ArrYGNZ/updUAACAAQAAgAAAAIAAAAAAAwAAAAAA"
}

>> sign --psbt cHNidP8BAHEBAAAAARAnt7YyE0GznP/9ddMvJj21UZJvYxePoPZzLKQaABqrAQAAAAD/////AuILAAAAAAAAFgAUR/J8qBUWz+VI4IPMZf9h4V2LbWmgDAAAAAAAABYAFJBTurBUcr77iCpb0tPmCOGy84ZrAAAAAAABAR8PGQAAAAAAABYAFEVWZq4wmchQmMHuTxXn5nJorLFiIgYD2buG/D7EDLZn7nsbD8JEpdDrJ//odPM1S6dLbxhwv7sY1n+6l1QAAIABAACAAAAAgAAAAAACAAAAACICA8EuowXeoqVzny4kvL5RrEiNBBDrKGQaXv7yEq+2ArrYGNZ/updUAACAAQAAgAAAAIAAAAAAAwAAAAAA
{
  "is_finalized": true,
  "psbt": "cHNidP8BAHEBAAAAARAnt7YyE0GznP/9ddMvJj21UZJvYxePoPZzLKQaABqrAQAAAAD/////
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"
}

>> broadcast --psbt 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
{
  "txid": "f6ef8179b7612a272205bd152d8e833b6b9ced11aedbb2678eb9ba211157bb12"
}

Building a 2-of-2 multisig transaction using PSBTs

The worflow for this is the following:

Create individual wallets for all parties
Create descriptor for the “common” wallet which will generate both receive addresses and enable signatures
Create the initial unsigned Partially Signed Bitcoin Transaction (PSBT)
Pass that psbt to Alice so she can sign it and produce an updated psbt
Pass that new psbt to Bob so he can sign it as well
Finalize the psbt
Broadcast the transaction to the network

First, let’s build our wallets.

# Alice
bdk-cli key generate --entropy 24
{
  "fingerprint": "6926972a",
  "mnemonic": "pulp clinic battle blast crumble tube orphan jungle eye swing vessel save like club situate dash female august wall danger street there embrace robot",
  "xprv": "tprv8ZgxMBicQKsPeG1VL2QFVJKtXJUGhRMUR5oZkqhNnd6GeX671mZTkfz9omTyVHvoZ6WnmectqWf1Lz4FLXmqnohpyg7HD7Lt6BavNkTAt6B"
}

# Create xpub descriptor wallet for Alice
bdk-cli wallet --descriptor "wpkh(tprv8ZgxMBicQKsPeG1VL2QFVJKtXJUGhRMUR5oZkqhNnd6GeX671mZTkfz9omTyVHvoZ6WnmectqWf1Lz4FLXmqnohpyg7HD7Lt6BavNkTAt6B/84h/1h/0h/0/*)" public_descriptor
{
  "external": "wpkh([6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*)#ymtz0gs6",
  "internal": null
}

# Bob
bdk-cli key generate --entropy 24
{
  "fingerprint": "a0ff6e5d",
  "mnemonic": "mistake hidden pull together affair card easily shell stumble wolf leisure swamp stamp error appear bachelor meat split negative feature slush disagree food control",
  "xprv": "tprv8ZgxMBicQKsPfFrtXpphYa3nrKfZEQK7UxQJi4oGWXAfhnhuFPa59R628kpptohy3qPsrjNpoVjfDhS8bcf2qdpgnwd4AdzrknrCCv8NSwR"
}

# Create xpub descriptor wallet for Bob
bdk-cli wallet --descriptor "wpkh(tprv8ZgxMBicQKsPfFrtXpphYa3nrKfZEQK7UxQJi4oGWXAfhnhuFPa59R628kpptohy3qPsrjNpoVjfDhS8bcf2qdpgnwd4AdzrknrCCv8NSwR/84h/1h/0h/0/*)" public_descriptor
{
  "external": "wpkh([a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*)#3fsvszk3",
  "internal": null
}

Next, we need a public descriptor for the common wallet between Alice and Bob. The descriptors for these types of wallets often use miniscript, and so you’ll often need to find the exact miniscript needed for the type of locking script you wish to impose on the addresses your wallet will generate. Once place to do that is in the playground on the bitcoindevkit website. Here we want a 2-of-2 multisig, which actually not to miniscript but to a simpler Pay to Witness Script Hash: wsh(multi(2,Alice,Bob)). We’ll start by building 3 versions of the wallet descriptors: a public one consisting of Alice and Bob’s xpubs, one where Alice has her xprv but doesn’t know Bob’s xprv, and a third one where Bob has Alice’s xpub and his xprv.

# wsh(multi(2,Alice,Bob))
# descriptor for the public wallet (no xprv)
"wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))"

# Alice's private version of the descriptor
"wsh(multi(2,tprv8ZgxMBicQKsPeG1VL2QFVJKtXJUGhRMUR5oZkqhNnd6GeX671mZTkfz9omTyVHvoZ6WnmectqWf1Lz4FLXmqnohpyg7HD7Lt6BavNkTAt6B/84h/1h/0h/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))"

# Bob's private version of the descriptor
"wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,tprv8ZgxMBicQKsPfFrtXpphYa3nrKfZEQK7UxQJi4oGWXAfhnhuFPa59R628kpptohy3qPsrjNpoVjfDhS8bcf2qdpgnwd4AdzrknrCCv8NSwR/84h/1h/0h/0/*))"

From here we have all we need to generate the PSBTs and sign them. To generate receive addresses and construct the unsigned empty initial PSBT, all we need is the public version of the wallet, and so that’s what we’ll derive here:

# build common public wallet for multisig and generate receive address
# note that this would have been the same address had we build the wallet using any of the 2 other descriptors above
bdk-cli wallet --descriptor "wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))" get_new_address
{
  "address": "tb1qnvqrz66zce2c8mxeajjv3hfwnu2sehf5rjcg4m27lftphu3rtlnqrvgsmt"
}

# *Send testnet coins to address above to fund the wallet and verify they have confirmed
# txid: 73a2aae654ce4176bb387e58b838682057be59fc69f8749279f4de5e062300b6

# Generate unsigned PSBT
# ***At this point we need the wallet to be funded and synced!***
bdk-cli wallet --descriptor "wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))" create_tx --to "tb1qm5tfegjevj27yvvna9elym9lnzcf0zraxgl8z2:0" --send_all
{
  "details": {
    "fees": 138,
    "height": null,
    "received": 0,
    "sent": 10000,
    "timestamp": 1613703354,
    "transaction": null,
    "txid": "948b6d5220043c1343f5569c35c5b33ab7b6159e9c8da5edd0f160a8c711f25d"
  },
  "psbt": "cHNidP8BAFIBAAAAAbYAIwZe3vR5knT4afxZvlcgaDi4WH44u3ZBzlTmqqJzAQAAAAD/////AYYmAAAAAAAAFgAU3RacollkleIxk+lz8my/mLCXiH0AAAAAAAEBKxAnAAAAAAAAIgAgmwAxa0LGVYPs2eykyN0unxUM3TQcsIrtXvpWG/IjX+YBBUdSIQJhHSuAC4OHocXzeQ0VSVQjaQuxrvTmkb6z0c03e8cO6iEDFeKxKo1lKpXfMZ3UNHaAKNCC+HkdE8E5kk9Epf1yldlSriIGAmEdK4ALg4ehxfN5DRVJVCNpC7Gu9OaRvrPRzTd7xw7qGGkmlypUAACAAQAAgAAAAIAAAAAAAAAAACIGAxXisSqNZSqV3zGd1DR2gCjQgvh5HRPBOZJPRKX9cpXZGKD/bl1UAACAAQAAgAAAAIAAAAAAAAAAAAAA"
}

We now have an unsigned PSBT ready to be passed around to the signators. Alice takes the first round and signs using her private wallet. This is a different descriptor than in the previous step, so you’ll either need to delete your bdk cache (rm -rf ~/.bdk-bitcoin/) or name your wallets (see examples in previous sections for how to do just that).

# Round 1: Alice signs the psbt
# ***Make sure Alice's new wallet is synced!***
bdk-cli wallet --descriptor "wsh(multi(2,tprv8ZgxMBicQKsPeG1VL2QFVJKtXJUGhRMUR5oZkqhNnd6GeX671mZTkfz9omTyVHvoZ6WnmectqWf1Lz4FLXmqnohpyg7HD7Lt6BavNkTAt6B/84h/1h/0h/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))" sign --psbt "cHNidP8BAFIBAAAAAbYAIwZe3vR5knT4afxZvlcgaDi4WH44u3ZBzlTmqqJzAQAAAAD/////AYYmAAAAAAAAFgAU3RacollkleIxk+lz8my/mLCXiH0AAAAAAAEBKxAnAAAAAAAAIgAgmwAxa0LGVYPs2eykyN0unxUM3TQcsIrtXvpWG/IjX+YBBUdSIQJhHSuAC4OHocXzeQ0VSVQjaQuxrvTmkb6z0c03e8cO6iEDFeKxKo1lKpXfMZ3UNHaAKNCC+HkdE8E5kk9Epf1yldlSriIGAmEdK4ALg4ehxfN5DRVJVCNpC7Gu9OaRvrPRzTd7xw7qGGkmlypUAACAAQAAgAAAAIAAAAAAAAAAACIGAxXisSqNZSqV3zGd1DR2gCjQgvh5HRPBOZJPRKX9cpXZGKD/bl1UAACAAQAAgAAAAIAAAAAAAAAAAAAA"
{
  "is_finalized": false,
  "psbt": "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"
}
# notice how the psbt is now bigger than it was before Alice signed it

# Bob signs the psbt
# ***Make sure Bob's wallet is synced!***
bdk-cli wallet --descriptor "wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,tprv8ZgxMBicQKsPfFrtXpphYa3nrKfZEQK7UxQJi4oGWXAfhnhuFPa59R628kpptohy3qPsrjNpoVjfDhS8bcf2qdpgnwd4AdzrknrCCv8NSwR/84h/1h/0h/0/*))" sign --psbt "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"
{
  "is_finalized": true,
  "psbt": "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"
}

Note that the returned object on the last signature shows the is_finalized key as true. This means the psbt is ready to be broadcast.

bdk-cli wallet --descriptor "wsh(multi(2,[6926972a/84'/1'/0']tpubDCj3FLoMDHpcfex7esm3hRw5xie6jDzrKpdJ4mLD95wZLdUHXoiw9tJAamG7gaTJb4yiLyGAAKwQah8c2yAoyR5UXtyY6xW3n8vNoWZMmdM/0/*,[a0ff6e5d/84'/1'/0']tpubDCqapM5b7JtmYwt1tcnPnk5e5Wqw6FKYsz1PutkRvmA6G653sCjFr4Qdhncgd4xTmG7BQgJtFkPCxP3jsS7byPUnDaS5FD3Ad7qoEfiamMe/0/*))" broadcast --psbt "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"
{
  "txid": "948b6d5220043c1343f5569c35c5b33ab7b6159e9c8da5edd0f160a8c711f25d"
}

That’s it! You can see the final transaction here.