signing

name

signing

description

This skill should be used when signing messages, authenticating HTTP requests, or doing counterparty cryptography with a BRC-100 wallet. Covers BSM (Bitcoin Signed Message) signing, BRC-77 auth tokens for signed HTTP requests, deriving a counterparty's Type-42 public key (ECDH friend key), and encrypting/decrypting data for a counterparty. Triggers on 'sign message', 'BSM', 'Bitcoin Signed Message', 'auth token', 'BRC-77', 'signed request', 'friend public key', 'Type-42', 'ECDH', 'encrypt for counterparty', 'decrypt from counterparty', or 'shared secret'. Uses @1sat/actions signing module.

Signing

Message signing, request authentication, and counterparty cryptography using @1sat/actions.

These actions only call the wallet's signing/key/crypto primitives — none of them build or broadcast transactions, so a plain createContext(wallet) is enough (no services required). All of them catch errors and return an error string rather than throwing.

const ctx = createContext(wallet)

signBsm

Signs a message in BSM (Bitcoin Signed Message) format. Hashes the message with BSM.magicHash, signs with the message-signing protocol, then returns a compact recoverable signature plus the signing address/pubkey. The tag selects the derivation key (keyID = "${tag.label}:${tag.id}:${tag.domain}"); without a tag the keyID is 'identity'.

import { createContext, signBsm } from '@1sat/actions'

const ctx = createContext(wallet)

// Input: SignBsmRequest
const res = await signBsm.execute(ctx, {
  message: 'hello world',
  encoding: 'utf8',        // optional: 'utf8' | 'hex' | 'base64' (default 'utf8')
  tag: {                   // optional derivation tag
    label: 'app',
    id: 'session-1',
    domain: 'example.com',
    meta: {},
  },
})

// Result: SignBsmResponse (Partial<SignedMessage> & { error?: string })
// {
//   address?: string       // signing address
//   pubKey?: string        // compressed pubkey hex
//   message?: string       // echoed message
//   sig?: string           // compact recoverable signature, base64
//   derivationTag?: { label; id; domain; meta }
//   error?: string
// }

signBsm is also referenced in the ../action-patterns primer; this is its canonical home.

getAuthToken

Generates a BRC-77 auth token for signing an HTTP request. It builds the message requestPath|timestamp|bodyHash (where bodyHash is the hex sha256 of the body, or empty if no body), signs it with a fresh random keyID under protocol [2, 'message signing'], and packs a BRC-77 envelope into the returned token.

import { createContext, getAuthToken } from '@1sat/actions'

const ctx = createContext(wallet)

// Input: AuthTokenRequest
const res = await getAuthToken.execute(ctx, {
  requestPath: '/api/resource?id=1', // include query params
  body: '{"foo":"bar"}',             // optional
  bodyEncoding: 'utf8',              // optional: 'utf8' | 'hex' | 'base64' (default 'utf8')
  timestamp: '2026-06-11T00:00:00Z', // optional ISO8601, defaults to now
})

// Result: AuthTokenResponse
// {
//   authToken?: string   // "<senderPubKeyHex>|brc77|<timestamp>|<requestPath>|<base64Envelope>"
//   error?: string
// }

The token's signature is computed over requestPath, timestamp, and bodyHash, so the verifier must reconstruct the same triple. The envelope is BRC77_VERSION || senderPubKey || 0x00 || keyID || derSignature, base64-encoded.

getFriendPublicKey

Derives a counterparty's public key using Type-42 (BRC-42) key derivation — the ECDH-style "friend key" for a given protocol/keyID against a counterparty identity key. Use this to compute the address/pubkey a counterparty would derive for you (or vice versa) under a shared protocol.

import { createContext, getFriendPublicKey } from '@1sat/actions'

const ctx = createContext(wallet)

// Input: FriendPubKeyRequest
const res = await getFriendPublicKey.execute(ctx, {
  friendIdentityKey: '02ab...', // counterparty identity key (compressed hex)
  protocolID: [2, 'my protocol'],
  keyID: 'invoice-42',
})

// Result: FriendPubKeyResponse
// { publicKey?: string; error?: string }

Internally calls wallet.getPublicKey({ protocolID, keyID, counterparty: friendIdentityKey, forSelf: false }).

encryptForCounterparty

Encrypts plaintext bytes for a counterparty using Type-42 derived keys. Pass counterparty: 'self' to encrypt to your own key.

import { createContext, encryptForCounterparty } from '@1sat/actions'

const ctx = createContext(wallet)

// Input: EncryptRequest
const res = await encryptForCounterparty.execute(ctx, {
  plaintext: [/* number[] bytes */],
  protocolID: [2, 'my protocol'],
  keyID: 'message-1',
  counterparty: '02ab...', // identity key hex or 'self'
})

// Result: EncryptResponse
// { ciphertext?: number[]; error?: string }

Internally calls wallet.encrypt({ protocolID, keyID, counterparty, plaintext }).

decryptFromCounterparty

Decrypts ciphertext bytes from a counterparty. Use the same protocolID, keyID, and counterparty the data was encrypted under.

import { createContext, decryptFromCounterparty } from '@1sat/actions'

const ctx = createContext(wallet)

// Input: DecryptRequest
const res = await decryptFromCounterparty.execute(ctx, {
  ciphertext: [/* number[] bytes */],
  protocolID: [2, 'my protocol'],
  keyID: 'message-1',
  counterparty: '02ab...', // identity key hex or 'self'
})

// Result: DecryptResponse
// { plaintext?: number[]; error?: string }

Internally calls wallet.decrypt({ protocolID, keyID, counterparty, ciphertext }).

Requirements

bun add @1sat/actions @bsv/sdk

These actions need only createContext(wallet) — no services.