@ledgerhq/hw-app-btc
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Ledger Hardware Wallet Bitcoin Application API
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@ledgerhq/hw-app-btc
Ledger Hardware Wallet BTC JavaScript bindings. Also supports many altcoins.
Are you adding Ledger support to your software wallet?
You may be using this package to communicate with the Bitcoin Nano App.
For a smooth and quick integration:
- See the developers’ documentation on the Developer Portal and
- Go on Discord to chat with developer support and the developer community.
API
Table of Contents
- bippath
- Btc
- BtcNew
- descrTemplFrom
- BtcOld
- CreateTransactionArg
- AddressFormat
- AccountType
- SingleKeyAccount
- getTaprootOutputKey
- AppClient
- ClientCommandInterpreter
- MerkelizedPsbt
- Merkle
- MerkleMap
- WalletPolicy
- extract
- finalize
- clearFinalizedInput
- writePush
- PsbtV2
- serializeTransactionOutputs
- SignP2SHTransactionArg
- TransactionInput
- TransactionOutput
- Transaction
bippath
BIP32 Path Handling for Bitcoin Wallets
This file provides utility functions to handle BIP32 paths, which are commonly used in hierarchical deterministic (HD) wallets. It includes functions to convert BIP32 paths to and from different formats, extract components from extended public keys (xpubs), and manipulate path elements.
Btc
Bitcoin API.
Parameters
transport
The transport layer used for communication.scrambleKey
This parameter is deprecated and no longer needed.currency
The currency to use, defaults to "bitcoin".
Examples
import Btc from "@ledgerhq/hw-app-btc";
const btc = new Btc({ transport, currency: "bitcoin" });
getWalletXpub
Get an XPUB with a ledger device
Parameters
arg
{path: string, xpubVersion: number} derivation parameter* path: a BIP 32 path of the account level. (e.g. The derivation path84'/0'/0'
follows thepurpose' / coin_type' / account'
standard, with purpose=84, coin_type=0, account=0)- xpubVersion: the XPUBVersion of the coin used. (refer to ledgerjs/packages/cryptoassets/src/currencies.ts for the XPUBVersion value if needed)
Returns Promise<string> XPUB of the account
getWalletPublicKey
Parameters
path
string a BIP 32 path (i.e. thepurpose’ / coin_type’ / account’ / change / address_index
standard)opts
{verify: boolean?, format: AddressFormat?}?options
an object with optional these fields:* verify (boolean) whether ask user to confirm the address on the deviceformat ("legacy" | "p2sh" | "bech32" | "bech32m" | "cashaddr") to use different bitcoin address formatter.NB The normal usage is to use:* legacy format with 44' paths
p2sh format with 49' paths
bech32 format with 84' paths
bech32m format with 86' paths
cashaddr in case of Bitcoin Cash
Examples
btc.getWalletPublicKey("44'/0'/0'/0/0").then(o => o.bitcoinAddress)
btc.getWalletPublicKey("49'/0'/0'/0/0", { format: "p2sh" }).then(o => o.bitcoinAddress)
Returns Promise<{publicKey: string, bitcoinAddress: string, chainCode: string}>
signMessage
You can sign a message according to the Bitcoin Signature format and retrieve v, r, s given the message and the BIP 32 path of the account to sign.
Parameters
Examples
btc.signMessage("44'/60'/0'/0'/0", Buffer.from("test").toString("hex")).then(function(result) {
var v = result['v'] + 27 + 4;
var signature = Buffer.from(v.toString(16) + result['r'] + result['s'], 'hex').toString('base64');
console.log("Signature : " + signature);
}).catch(function(ex) {console.log(ex);});
Returns Promise<{v: number, r: string, s: string}>
createPaymentTransaction
To sign a transaction involving standard (P2PKH) inputs, call createTransaction with the following parameters
Parameters
arg
CreateTransactionArginputs
is an array of [ transaction, output_index, optional redeem script, optional sequence ] where* transaction is the previously computed transaction object for this UTXO- output_index is the output in the transaction used as input for this UTXO (counting from 0)
- redeem script is the optional redeem script to use when consuming a Segregated Witness input
- sequence is the sequence number to use for this input (when using RBF), or non present
associatedKeysets
is an array of BIP 32 paths pointing to the path to the private key used for each UTXOchangePath
is an optional BIP 32 path pointing to the path to the public key used to compute the change addressoutputScriptHex
is the hexadecimal serialized outputs of the transaction to sign, including leading vararg voutCountlockTime
is the optional lockTime of the transaction to sign, or default (0)sigHashType
is the hash type of the transaction to sign, or default (all)segwit
is an optional boolean indicating wether to use segwit or not. This includes wrapped segwit.additionals
list of additionnal options* "bech32" for spending native segwit outputs- "bech32m" for spending segwit v1+ outputs
- "abc" for bch
- "gold" for btg
- "decred" for decred
- "zcash" for zcash
- "bipxxx" for using BIPxxx
- "sapling" to indicate a zec transaction is supporting sapling (to be set over block 419200)
expiryHeight
is an optional Buffer for zec overwinter / sapling TxsuseTrustedInputForSegwit
trust inputs for segwit transactions. If app version >= 1.4.0 this should be true.
Examples
btc.createTransaction({
inputs: [ [tx1, 1] ],
associatedKeysets: ["0'/0/0"],
outputScriptHex: "01905f0100000000001976a91472a5d75c8d2d0565b656a5232703b167d50d5a2b88ac"
}).then(res => ...);
Returns Promise<string> the signed transaction ready to be broadcast
signP2SHTransaction
To obtain the signature of multisignature (P2SH) inputs, call signP2SHTransaction_async with the folowing parameters
Parameters
arg
SignP2SHTransactionArginputs
is an array of [ transaction, output_index, redeem script, optional sequence ] where* transaction is the previously computed transaction object for this UTXO- output_index is the output in the transaction used as input for this UTXO (counting from 0)
- redeem script is the mandatory redeem script associated to the current P2SH input
- sequence is the sequence number to use for this input (when using RBF), or non present
associatedKeysets
is an array of BIP 32 paths pointing to the path to the private key used for each UTXOoutputScriptHex
is the hexadecimal serialized outputs of the transaction to signlockTime
is the optional lockTime of the transaction to sign, or default (0)sigHashType
is the hash type of the transaction to sign, or default (all)
Examples
btc.signP2SHTransaction({
inputs: [ [tx, 1, "52210289b4a3ad52a919abd2bdd6920d8a6879b1e788c38aa76f0440a6f32a9f1996d02103a3393b1439d1693b063482c04bd40142db97bdf139eedd1b51ffb7070a37eac321030b9a409a1e476b0d5d17b804fcdb81cf30f9b99c6f3ae1178206e08bc500639853ae"] ],
associatedKeysets: ["0'/0/0"],
outputScriptHex: "01905f0100000000001976a91472a5d75c8d2d0565b656a5232703b167d50d5a2b88ac"
}).then(result => ...);
Returns Promise<Array<string>> the signed transaction ready to be broadcast
splitTransaction
For each UTXO included in your transaction, create a transaction object from the raw serialized version of the transaction used in this UTXO.
Parameters
transactionHex
string a raw hexadecimal serialized transactionisSegwitSupported
(boolean | null | undefined) is a boolean indicating if the segwit is supported (optional, defaultfalse
)hasExtraData
is a boolean (komodo, zencash and zcash include extraData in their transactions, others don't) (optional, defaultfalse
)additionals
Array<string> list of additionnal options (optional, default[]
)
Examples
const tx1 = btc.splitTransaction("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");
Returns Transaction the transaction object deserialized from the raw hexadecimal transaction
serializeTransactionOutputs
Serialize a transaction's outputs to hexadecimal
Parameters
Examples
const tx1 = btc.splitTransaction("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");
const outputScript = btc.serializeTransactionOutputs(tx1).toString('hex');
Returns Buffer
getTrustedInput
Trusted input is the hash of a UTXO that needs to be signed For Legacy transactions, the app has some APDUs flows that do the amount check for an UTXO, by parsing the transaction that created this UTXO
Parameters
indexLookup
numbertransaction
Transactionadditionals
Array<string> (optional, default[]
)
getTrustedInputBIP143
Trusted input is the hash of a UTXO that needs to be signed. BIP143 is used for Segwit inputs.
Parameters
indexLookup
numbertransaction
Transactionadditionals
Array<string> (optional, default[]
)
Returns string
BtcNew
This class implements the same interface as BtcOld (formerly named Btc), but interacts with Bitcoin hardware app version 2.1.0+ which uses a totally new APDU protocol. This new protocol is documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/bitcoin.md
Since the interface must remain compatible with BtcOld, the methods of this class are quite clunky, because it needs to adapt legacy input data into the PSBT process. In the future, a new interface should be developed that exposes PSBT to the outer world, which would render a much cleaner implementation.
getWalletXpub
This is a new method that allow users to get an xpub at a standard path. Standard paths are described at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/bitcoin.md#description
This boils down to paths (N=0 for Bitcoin, N=1 for Testnet): M/44'/N'/x'/** M/48'/N'/x'/y'/** M/49'/N'/x'/** M/84'/N'/x'/** M/86'/N'/x'/**
The method was added because of added security in the hardware app v2+. The new hardware app will allow export of any xpub up to and including the deepest hardened key of standard derivation paths, whereas the old app would allow export of any key.
This caused an issue for callers of this class, who only had getWalletPublicKey() to call which means they have to constuct xpub themselves:
Suppose a user of this class wants to create an account xpub on a standard path, M/44'/0'/Z'. The user must get the parent key fingerprint (see BIP32) by requesting the parent key M/44'/0'. The new app won't allow that, because it only allows exporting deepest level hardened path. So the options are to allow requesting M/44'/0' from the app, or to add a new function "getWalletXpub".
We opted for adding a new function, which can greatly simplify client code.
Parameters
getWalletPublicKey
This method returns a public key, a bitcoin address, and and a chaincode for a specific derivation path.
Limitation: If the path is not a leaf node of a standard path, the address will be the empty string "", see this.getWalletAddress() for details.
Parameters
path
stringopts
{verify: boolean?, format: AddressFormat?}?
Returns Promise<{publicKey: string, bitcoinAddress: string, chainCode: string}>
createPaymentTransaction
Build and sign a transaction. See Btc.createPaymentTransaction for details on how to use this method.
This method will convert the legacy arguments, CreateTransactionArg, into a psbt which is finally signed and finalized, and the extracted fully signed transaction is returned.
Parameters
signMessage
Signs an arbitrary hex-formatted message with the private key at the provided derivation path according to the Bitcoin Signature format and returns v, r, s.
Parameters
Returns Promise<{v: number, r: string, s: string}>
descrTemplFrom
This function returns a descriptor template based on the address format. See https://github.com/LedgerHQ/app-bitcoin-new/blob/develop/doc/wallet.md for details of the bitcoin descriptor template.
Parameters
addressFormat
AddressFormat
Returns DefaultDescriptorTemplate
BtcOld
This Bitcoin old API is compatible with versions of the Bitcoin nano app that are earlier than 2.1.0
getWalletPublicKey
Parameters
path
string a BIP 32 pathopts
{verify: boolean?, format: AddressFormat?}?options
an object with optional these fields:* verify (boolean) will ask user to confirm the address on the deviceformat ("legacy" | "p2sh" | "bech32" | "bech32m" | "cashaddr") to use different bitcoin address formatter.NB The normal usage is to use:* legacy format with 44' paths
p2sh format with 49' paths
bech32 format with 84' paths
bech32m format with 86' paths
cashaddr in case of Bitcoin Cash
Examples
btc.getWalletPublicKey("44'/0'/0'/0/0").then(o => o.bitcoinAddress)
btc.getWalletPublicKey("49'/0'/0'/0/0", { format: "p2sh" }).then(o => o.bitcoinAddress)
Returns Promise<{publicKey: string, bitcoinAddress: string, chainCode: string}>
createPaymentTransaction
To sign a transaction involving standard (P2PKH) inputs, call createTransaction with the following parameters
Parameters
arg
CreateTransactionArginputs
is an array of [ transaction, output_index, optional redeem script, optional sequence ] where* transaction is the previously computed transaction object for this UTXO- output_index is the output in the transaction used as input for this UTXO (counting from 0)
- redeem script is the optional redeem script to use when consuming a Segregated Witness input
- sequence is the sequence number to use for this input (when using RBF), or non present
associatedKeysets
is an array of BIP 32 paths pointing to the path to the private key used for each UTXOchangePath
is an optional BIP 32 path pointing to the path to the public key used to compute the change addressoutputScriptHex
is the hexadecimal serialized outputs of the transaction to signlockTime
is the optional lockTime of the transaction to sign, or default (0)sigHashType
is the hash type of the transaction to sign, or default (all)segwit
is an optional boolean indicating wether to use segwit or notadditionals
list of additionnal options* "bech32" for spending native segwit outputs- "abc" for bch
- "gold" for btg
- "decred" for decred
- "zcash" for zcash
- "bipxxx" for using BIPxxx
- "sapling" to indicate a zec transaction is supporting sapling (to be set over block 419200)
expiryHeight
is an optional Buffer for zec overwinter / sapling TxsuseTrustedInputForSegwit
trust inputs for segwit transactions
Examples
btc.createTransaction({
inputs: [ [tx1, 1] ],
associatedKeysets: ["0'/0/0"],
outputScriptHex: "01905f0100000000001976a91472a5d75c8d2d0565b656a5232703b167d50d5a2b88ac"
}).then(res => ...);
Returns Promise<string> the signed transaction ready to be broadcast
CreateTransactionArg
Type: {inputs: Array<[Transaction, number, (string | null | undefined), (number | null | undefined)]>, associatedKeysets: Array<string>, changePath: string?, outputScriptHex: string, lockTime: number?, sigHashType: number?, segwit: boolean?, additionals: Array<string>, expiryHeight: Buffer?, useTrustedInputForSegwit: boolean?, onDeviceStreaming: function (arg0: {progress: number, total: number, index: number}): void?, onDeviceSignatureRequested: function (): void?, onDeviceSignatureGranted: function (): void?}
Properties
inputs
Array<[Transaction, number, (string | null | undefined), (number | null | undefined)]>associatedKeysets
Array<string>changePath
string?outputScriptHex
stringlockTime
number?sigHashType
number?segwit
boolean?additionals
Array<string>expiryHeight
Buffer?useTrustedInputForSegwit
boolean?onDeviceStreaming
function (arg0: {progress: number, total: number, index: number}): void?onDeviceSignatureRequested
function (): void?onDeviceSignatureGranted
function (): void?
AddressFormat
address format is one of legacy | p2sh | bech32 | bech32m | cashaddr
Type: ("legacy"
| "p2sh"
| "bech32"
| "bech32m"
| "cashaddr"
)
AccountType
Encapsulates differences between account types, for example p2wpkh, p2wpkhWrapped, p2tr.
spendingCondition
Generates a scriptPubKey (output script) from a list of public keys. If a p2sh redeemScript or a p2wsh witnessScript is needed it will also be set on the returned SpendingCondition.
The pubkeys are expected to be 33 byte ecdsa compressed pubkeys.
Parameters
Returns SpendingCondition
setInput
Populates the psbt with account type-specific data for an input.
Parameters
i
number The index of the input map to populateinputTx
(Buffer | undefined) The full transaction containing the spent output. This may be omitted for taproot.spentOutput
SpentOutput The amount and spending condition of the spent outputpubkeys
Array<Buffer> The 33 byte ecdsa compressed public keys involved in the inputpathElems
Array<Array<number>> The paths corresponding to the pubkeys, in same order.
Returns void
setOwnOutput
Populates the psbt with account type-specific data for an output. This is typically done for change outputs and other outputs that goes to the same account as being spent from.
Parameters
i
number The index of the output map to populatecond
SpendingCondition The spending condition for this outputpubkeys
Array<Buffer> The 33 byte ecdsa compressed public keys involved in this outputpaths
Array<Array<number>> The paths corresponding to the pubkeys, in same order.
Returns void
getDescriptorTemplate
Returns the descriptor template for this account type. Currently only DefaultDescriptorTemplates are allowed, but that might be changed in the future. See class WalletPolicy for more information on descriptor templates.
Returns DefaultDescriptorTemplate
SingleKeyAccount
Extends BaseAccount
Superclass for single signature accounts. This will make sure that the pubkey arrays and path arrays in the method arguments contains exactly one element and calls an abstract method to do the actual work.
getTaprootOutputKey
Calculates a taproot output key from an internal key. This output key will be used as witness program in a taproot output. The internal key is tweaked according to recommendation in BIP341: https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#cite_ref-22-0
Parameters
internalPubkey
Buffer A 32 byte x-only taproot internal key
Returns Buffer The output key
AppClient
This class encapsulates the APDU protocol documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/bitcoin.md
Parameters
transport
Transport
ClientCommandInterpreter
This class will dispatch a client command coming from the hardware device to the appropriate client command implementation. Those client commands typically requests data from a merkle tree or merkelized maps.
A ClientCommandInterpreter is prepared by adding the merkle trees and merkelized maps it should be able to serve to the hardware device. This class doesn't know anything about the semantics of the data it holds, it just serves merkle data. It doesn't even know in what context it is being executed, ie SignPsbt, getWalletAddress, etc.
If the command yelds results to the client, as signPsbt does, the yielded data will be accessible after the command completed by calling getYielded(), which will return the yields in the same order as they came in.
Parameters
progressCallback
function (): void
MerkelizedPsbt
Extends PsbtV2
This class merkelizes a PSBTv2, by merkelizing the different maps of the psbt. This is used during the transaction signing process, where the hardware app can request specific parts of the psbt from the client code and be sure that the response data actually belong to the psbt. The reason for this is the limited amount of memory available to the app, so it can't always store the full psbt in memory.
The signing process is documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/bitcoin.md#sign_psbt
Parameters
psbt
PsbtV2
Merkle
This class implements the merkle tree used by Ledger Bitcoin app v2+, which is documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/merkle.md
Parameters
MerkleMap
This implements "Merkelized Maps", documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/merkle.md#merkleized-maps
A merkelized map consist of two merkle trees, one for the keys of a map and one for the values of the same map, thus the two merkle trees have the same shape. The commitment is the number elements in the map followed by the keys' merkle root followed by the values' merkle root.
Parameters
keys
Array<Buffer> Sorted list of (unhashed) keysvalues
Array<Buffer> values, in corresponding order as the keys, and of equal length
WalletPolicy
The Bitcon hardware app uses a descriptors-like thing to describe how to construct output scripts from keys. A "Wallet Policy" consists of a "Descriptor Template" and a list of "keys". A key is basically a serialized BIP32 extended public key with some added derivation path information. This is documented at https://github.com/LedgerHQ/app-bitcoin-new/blob/master/doc/wallet.md
Parameters
descriptorTemplate
DefaultDescriptorTemplatekey
string
extract
This implements the "Transaction Extractor" role of BIP370 (PSBTv2 https://github.com/bitcoin/bips/blob/master/bip-0370.mediawiki#transaction-extractor). However the role is partially documented in BIP174 (PSBTv0 https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki#transaction-extractor).
Parameters
psbt
PsbtV2
Returns Buffer
finalize
This roughly implements the "input finalizer" role of BIP370 (PSBTv2 https://github.com/bitcoin/bips/blob/master/bip-0370.mediawiki). However the role is documented in BIP174 (PSBTv0 https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki).
Verify that all inputs have a signature, and set inputFinalScriptwitness and/or inputFinalScriptSig depending on the type of the spent outputs. Clean fields that aren't useful anymore, partial signatures, redeem script and derivation paths.
Parameters
psbt
PsbtV2 The psbt with all signatures added as partial sigs, either through PSBT_IN_PARTIAL_SIG or PSBT_IN_TAP_KEY_SIG
Returns void
clearFinalizedInput
Deletes fields that are no longer neccesary from the psbt.
Note, the spec doesn't say anything about removing ouput fields like PSBT_OUT_BIP32_DERIVATION_PATH and others, so we keep them without actually knowing why. I think we should remove them too.
Parameters
writePush
Writes a script push operation to buf, which looks different depending on the size of the data. See https://en.bitcoin.it/wiki/Script#Constants
Parameters
buf
BufferWriter the BufferWriter to write todata
Buffer the Buffer to be pushed.
PsbtV2
Implements Partially Signed Bitcoin Transaction version 2, BIP370, as documented at https://github.com/bitcoin/bips/blob/master/bip-0370.mediawiki and https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
A psbt is a data structure that can carry all relevant information about a transaction through all stages of the signing process. From constructing an unsigned transaction to extracting the final serialized transaction ready for broadcast.
This implementation is limited to what's needed in ledgerjs to carry out its duties, which means that support for features like multisig or taproot script path spending are not implemented. Specifically, it supports p2pkh, p2wpkhWrappedInP2sh, p2wpkh and p2tr key path spending.
This class is made purposefully dumb, so it's easy to add support for complemantary fields as needed in the future.
serializeTransactionOutputs
Parameters
$0
Transaction$0.outputs
Examples
const tx1 = btc.splitTransaction("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");
const outputScript = btc.serializeTransactionOutputs(tx1).toString('hex');
Returns Buffer
SignP2SHTransactionArg
Type: {inputs: Array<[Transaction, number, (string | null | undefined), (number | null | undefined)]>, associatedKeysets: Array<string>, outputScriptHex: string, lockTime: number?, sigHashType: number?, segwit: boolean?, transactionVersion: number?}
Properties
inputs
Array<[Transaction, number, (string | null | undefined), (number | null | undefined)]>associatedKeysets
Array<string>outputScriptHex
stringlockTime
number?sigHashType
number?segwit
boolean?transactionVersion
number?