TypeScript implementation of the Data Integrity BIP340 Cryptosuite v0.1 specification.
Part of the did-btcr2-js monorepo.
This package produces and verifies method-agnostic Data Integrity proofs; its primary consumer is did:btcr2, whose updates it authenticates. A secured document is any JSON object plus a proof block carrying a BIP-340 Schnorr signature over the JCS-canonicalized payload.
BIP340Cryptosuite creates and verifies proofs for the bip340-jcs-2025 suite (JCS-canonicalized hashing).BIP340DataIntegrityProof is the proof-construction primitive: builds the proof config, hashes the canonical bytes, calls into a Signer for the actual signature, and assembles the final proof block.SchnorrMultikey is the verification-method wrapper used in DID documents. It binds a SchnorrKeyPair to its multibase encoding (zQ3s...), supports watch-only verification, and accepts an injected Signer so production code never has to pass raw secret bytes.The cryptosuite is what links the abstract Signer interface from @did-btcr2/keypair to the on-disk shape of a signed DID update.
npm install @did-btcr2/cryptosuite
Or with pnpm:
pnpm add @did-btcr2/cryptosuite
The package ships both ESM (dist/esm/) and CJS (dist/cjs/) via conditional exports, so it works with import and require out of the box.
| Concern | Entry point |
|---|---|
| Build / verify proofs | BIP340Cryptosuite, Cryptosuite, VerificationResult |
| Proof primitive | BIP340DataIntegrityProof, DataIntegrityProof, DataIntegrityProofObject |
| Document payload types | UnsecuredDocument, SecuredDocument |
| Verification method wrapper | SchnorrMultikey, Multikey, MultikeyObject |
| Construction helpers | FromSecretKey, FromPublicKey |
| Proof options | DataIntegrityProofOptions |
import { SchnorrMultikey } from '@did-btcr2/cryptosuite';
import { Secp256k1SecretKey } from '@did-btcr2/keypair';
const controller = 'did:btcr2:k1q5p...';
const id = '#initialKey';
const secretKeyBytes = new Secp256k1SecretKey(rawSecretBytes).bytes; // 32-byte Uint8Array
const multikey = SchnorrMultikey.fromSecretKey(id, controller, secretKeyBytes);
const unsigned = { /* UnsecuredDocument: any JSON object to add a proof to (e.g. an unsigned did:btcr2 update) */ };
const config = {
'@context' : ['https://w3id.org/security/v2', 'https://w3id.org/zcap/v1', 'https://w3id.org/json-ld-patch/v1', 'https://btcr2.dev/context/v1'],
type : 'DataIntegrityProof' as const,
cryptosuite : 'bip340-jcs-2025',
proofPurpose : 'capabilityInvocation',
verificationMethod : `${controller}${id}`,
};
const proof = multikey.toCryptosuite().createProof(unsigned, config);
// proof.cryptosuite === 'bip340-jcs-2025'
import { SchnorrMultikey } from '@did-btcr2/cryptosuite';
// Reconstruct the multikey from the DID verification method.
// verificationMethod is a DidVerificationMethod with id, controller, publicKeyMultibase.
const multikey = SchnorrMultikey.fromVerificationMethod(verificationMethod);
const result = multikey.toCryptosuite().verifyProof(signedUpdate);
if (!result.verified) {
throw new Error('DI proof failed');
}
import { SchnorrMultikey } from '@did-btcr2/cryptosuite';
// kmsSigner implements Signer: { publicKey: Uint8Array; sign(data, scheme): SignatureBytes }
const controller = 'did:btcr2:k1q5p...';
const id = '#initialKey';
const multikey = SchnorrMultikey.fromSigner(id, controller, kmsSigner);
const config = {
'@context' : ['https://w3id.org/security/v2', 'https://w3id.org/zcap/v1', 'https://w3id.org/json-ld-patch/v1', 'https://btcr2.dev/context/v1'],
type : 'DataIntegrityProof' as const,
cryptosuite : 'bip340-jcs-2025',
proofPurpose : 'capabilityInvocation',
verificationMethod : `${controller}${id}`,
};
const proof = multikey.toCryptosuite().createProof(unsigned, config);
fromSigner seeds the multikey’s public key from kmsSigner.publicKey and delegates all signing to the signer, so no secret bytes ever enter the JS process. A public-key mismatch at construction time throws immediately.
@did-btcr2/common owns the canonicalization function; the cryptosuite just calls it.Signer. LocalSigner, KeyManagerSigner, and arbitrary user-provided implementations all work without code changes in this package.SchnorrMultikey constructed with a mismatched keyPair and externalSigner rejects at construction. A multibase string with the wrong [0xe7, 0x01] prefix rejects in fromVerificationMethod.bitcoinjs-lib. Curve, Schnorr, and hash operations delegate to @noble/curves and @noble/hashes. Proof encoding uses multiformats (base58btc), and verification-method types come from @web5/dids.# From packages/cryptosuite/
pnpm build # Compile ESM + CJS + type declarations
pnpm build:tests # Compile tests to tests/compiled/
pnpm test # Run the test suite with coverage
pnpm lint # ESLint (zero warnings tolerated)
BIP340Cryptosuite, BIP340DataIntegrityProof, and SchnorrMultikey.