@pdtf/core (TypeScript)

The TypeScript reference implementation of PDTF 2.0. All core functionality in a single dependency.

npm install @pdtf/core

Repository: property-data-standards-co/core-ts

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Modules

keys

Ed25519 key generation and did:key derivation.

import { generateKeyPair, deriveDidKey, publicKeyToMultibase } from '@pdtf/core';

const keypair = generateKeyPair();
// { publicKey: Uint8Array, secretKey: Uint8Array }

const did = deriveDidKey(keypair.publicKey);
// did:key:z6Mk...

const multibase = publicKeyToMultibase(keypair.publicKey);
// z6Mk...

Keys use the 0xed01 multicodec prefix with base58-btc encoding (z prefix). All PDTF did:key identifiers start with did:key:z6Mk.

Key Providers

@pdtf/core ships with four KeyProvider implementations for different environments:

Provider	Backend	Use case	Install
InMemoryKeyProvider	RAM	Unit tests	Built-in
SqliteKeyProvider	Local file	Dev / third-party testing	npm i better-sqlite3
FirestoreKeyProvider	Firestore	Staging	npm i @google-cloud/firestore
KmsKeyProvider	GCP Cloud KMS (HSM)	Production	npm i @google-cloud/kms

import { SqliteKeyProvider, VcSigner } from '@pdtf/core';

// Zero-config local key management
const keys = new SqliteKeyProvider({ dbPath: './pdtf-keys.db' });
const key = await keys.generateKey('my-adapter', 'adapter');
const signer = new VcSigner(keys, 'my-adapter', key.did);

// Start signing credentials
const vc = await signer.sign({
  type: 'PropertyDataCredential',
  credentialSubject: {
    id: 'urn:pdtf:uprn:100023336956',
    energyEfficiency: { rating: 'B', score: 85 },
  },
});

For production with Cloud KMS:

import { KmsKeyProvider, VcSigner } from '@pdtf/core';

const keys = new KmsKeyProvider({
  projectId: 'my-project',
  locationId: 'europe-west2',
  keyRingId: 'pdtf',
});
const key = await keys.generateKey('epc-adapter', 'adapter');
const signer = new VcSigner(keys, 'epc-adapter', key.did);

See the Key Management guide for full setup instructions.

signer

Create DataIntegrityProof signatures using eddsa-jcs-2022.

import { VcSigner } from '@pdtf/core';

const signer = new VcSigner(keyProvider);
const signed = await signer.sign(credential, {
  keyId: 'my-key',
  verificationMethod: 'did:key:z6Mk...#z6Mk...',
});

Signing algorithm (eddsa-jcs-2022):

1. JCS-canonicalize proof options → SHA-256 hash
2. JCS-canonicalize document (without proof) → SHA-256 hash
3. Concatenate both hashes (64 bytes)
4. Sign with Ed25519 (raw, not pre-hashed)
5. Encode signature as base58-btc (z prefix)

validator

Verify DataIntegrityProof signatures.

import { verifyProof } from '@pdtf/core';

const valid = verifyProof(signedCredential, publicKey);
// true | false

did

DID resolution for did:key and URN identifiers (urn:pdtf:uprn:*, urn:pdtf:titleNumber:*).

import { resolveDidKey, TransactionDidManager } from '@pdtf/core';

// Resolve did:key to DID Document
const doc = resolveDidKey('did:key:z6Mk...');

// Transaction DID lifecycle
const manager = new TransactionDidManager(config);
const txDid = await manager.create({ uprn: '100023336956' });

status

Bitstring Status List — create, encode, decode, and check credential revocation.

import { createStatusList, encodeStatusList, decodeStatusList, setBit, getBit } from '@pdtf/core';

const list = createStatusList(131072);  // 131,072-bit minimum
setBit(list, 42);
const encoded = encodeStatusList(list); // base64(gzip(bitstring))

const decoded = decodeStatusList(encoded);
const isRevoked = getBit(decoded, 42);  // true

tir

Trusted Issuer Registry client — load and validate issuer authorisations.

import { loadRegistry, isAuthorised } from '@pdtf/core';

const registry = await loadRegistry('https://github.com/property-data-standards-co/tir');
const result = isAuthorised(registry, issuerDid, ['Property:/energyEfficiency/certificate']);
// { trusted: true, issuerSlug: 'epc-adapter', trustLevel: 'rootIssuer', ... }

Path matching: The TIR supports wildcard patterns:

• Property:/energyEfficiency/certificate — exact match
• Property:/energyEfficiency/* — matches any path under /energyEfficiency/
• Property:* — matches any Property path

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CLI

Five commands for development and testing:

# Resolve a DID document
npx @pdtf/core did-resolve did:key:z6Mk...

# Initialise an organisation DID
npx @pdtf/core org-init --domain example.com --output ./keys

# Validate a TIR registry file
npx @pdtf/core tir-validate ./registry.json

# Inspect a VC (print structure without verification)
npx @pdtf/core vc-inspect ./credential.json

# Verify a VC signature
npx @pdtf/core vc-verify ./credential.json

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Tests

86 tests covering all modules:

Module	Tests	Coverage
keys	17	Key generation, did:key derivation, roundtrip, multibase encoding, SQLite provider, KMS provider
signer	3	Proof creation, deterministic signing, proof structure
did	29	Transaction DID manager, URN parsing, did:key resolution
status	7	Create, encode/decode, set/get bits, roundtrip
tir	7	Path matching, wildcard semantics, edge cases
vectors	17	Cross-language vector generation and self-validation

npm test