Add ability to generate DID from seed.

CHANGELOG.md

@@ -5,10 +5,15 @@
 ### `14.0.0-beta.2` - 2021-08-19
 
 ### Added
-- Add `driver.getInitial()` method, to explicitly construct a DID Document deterministically, from a cryptonym DID. 
+- Add `driver.getInitial()` method, to explicitly construct a DID Document
+  deterministically, from a cryptonym DID.
+- Add an optional `seed` param to `generate()` to generate DID documment from
+  a 32-byte array seed.
+
 
 ### Changed
-- **BREAKING**: Replaced axios with @digitalbazaar/http-client. Errors returned directly from http-client do not match the axios API.
+- **BREAKING**: Replaced axios with @digitalbazaar/http-client. Errors returned
+  directly from http-client do not match the axios API.
 - Changed API `getTicketServiceProof` to use `@digitalbazaar/http-client`.
 - Changed API `sendToAccelerator` to use `@digitalbazaar/http-client`.
 - **BREAKING**: API attachInvocationProof now requires the parameter `invocationTarget`.
@@ -19,7 +24,7 @@
 ### Changed
 - **BREAKING**: Change in `generate()` semantics to support the common un-registered
   DID use case. (See the "Upgrading from `<=12.x` section" below, item 1.)
-  Now, `generate()` now only generates one key, for `capabilityInvocation` but 
+  Now, `generate()` now only generates one key, for `capabilityInvocation` but
   also all the other purposes (much like generating a new `did:key` DID).
   (Helper libraries are expected to generate other keys before registering the
   DID Document on the ledger.)
@@ -38,7 +43,7 @@
 ### Upgrading from <=12.x
 
 **1)** DID Document `generate()` method return signature has changed.
-Change in `generate()` semantics (as of `v14.0.0-beta.1`). Since we expect using 
+Change in `generate()` semantics (as of `v14.0.0-beta.1`). Since we expect using
 an un-registered Veres One DID to be a common use case, the previous `generate()`
 behavior introduced complications, since different keys for each proof purpose
 were created by default. Except that, for the case of un-registered DIDs, the
@@ -69,14 +74,14 @@ public/private key pair instance that is referenced in the DID Document's
 `capabilityInvocation` verification relationship.
 
 **2)** Driver `.get()` method has changed -- no longer uses the `forceConstruct`
-parameter. Developers are encouraged to use the CachedResolver from 
+parameter. Developers are encouraged to use the CachedResolver from
 https://github.com/digitalbazaar/did-io instead.
 `driver.get()` can still be used to fetch either the full DID Document (via
 `await driver.get({did})`) or a key document (via `await driver.get({url: keyId})`).
 
 **3)** Check for `.computeKeyId()` usage. It's been renamed to `.computeId()`.
 
-**4)** Validation methods have changed (used by the `did-veres-one` validator 
+**4)** Validation methods have changed (used by the `did-veres-one` validator
 node):
 
 - `didDocument.validateDid({mode})` becomes:

lib/VeresOneDriver.js

@@ -196,12 +196,12 @@ class VeresOneDriver {
    */
   async generate({
     didType = DEFAULT_DID_TYPE, invokeKey, authKey, delegateKey, assertionKey,
-    keyAgreementKey
+    keyAgreementKey, seed
   } = {}) {
     const {mode, cryptoLd, verificationSuite} = this;
     return VeresOneDriver.generate({
       didType, cryptoLd, verificationSuite, mode, invokeKey, authKey,
-      delegateKey, assertionKey, keyAgreementKey
+      delegateKey, assertionKey, keyAgreementKey, seed
     });
   }
 
@@ -223,24 +223,30 @@ class VeresOneDriver {
    * @param {LDKeyPair} [options.delegateKey] - Capability delegation key pair.
    * @param {LDKeyPair} [options.assertionKey] - Assertion method key pair.
    * @param {LDKeyPair} [options.keyAgreementKey] - Key agreement key pair.
-   *
+   * @param {Uint8Array} [options.seed] - A 32-byte array seed for a
+   *   deterministic key.
    * @returns {Promise<{didDocument: object, keyPairs: Map,
    *   methodFor: Function}>} Resolves with the generated DID Document, along
    *   with the corresponding key pairs used to generate it.
    */
   static async generate({
     didType = DEFAULT_DID_TYPE, cryptoLd, mode,
     verificationSuite = DEFAULT_VERIFICATION_SUITE,
-    invokeKey, authKey, delegateKey, assertionKey, keyAgreementKey
+    invokeKey, authKey, delegateKey, assertionKey, keyAgreementKey, seed
   } = {}) {
     const cryptoSuiteContexts = new Set();
     const keyPairs = new Map();
     const keyType = verificationSuite.suite;
 
     // Before we initialize the rest of the keys, we need to compose the DID
     // Document `.id` itself, from the capabilityInvocation key pair.
-    const capabilityInvocationKeyPair = invokeKey ||
-      await cryptoLd.generate({type: keyType});
+    let capabilityInvocationKeyPair;
+    if(seed) {
+      capabilityInvocationKeyPair = await verificationSuite.generate({seed});
+    } else {
+      capabilityInvocationKeyPair = invokeKey ||
+        await cryptoLd.generate({type: keyType});
+    }
     cryptoSuiteContexts
       .add(capabilityInvocationKeyPair.constructor.SUITE_CONTEXT);
 

test/VeresOneDriver.spec.js

@@ -11,6 +11,7 @@ const {expect} = chai;
 
 const {Ed25519VerificationKey2020} =
   require('@digitalbazaar/ed25519-verification-key-2020');
+const {randomBytes} = require('crypto');
 
 const {CryptoLD} = require('crypto-ld');
 const {VeresOneDriver} = require('..');
@@ -173,6 +174,23 @@ describe('methods/veres-one', () => {
       expect(didDocument.id).to.match(/^did:v1:nym:z.*/);
     });
 
+    it('should create a DID document from seed', async () => {
+      const seed = randomBytes(32);
+      const {didDocument} = await driver.generate({seed});
+      console.log(JSON.stringify(didDocument, null, 2), 'didDocument');
+      expect(didDocument).to.have.keys([
+        '@context', 'id', 'authentication', 'assertionMethod',
+        'capabilityDelegation', 'capabilityInvocation', 'keyAgreement'
+      ]);
+      expect(didDocument.id).to.match(/^did:v1:test:nym:z.*/);
+      expect(didDocument['@context']).to.eql([
+        'https://www.w3.org/ns/did/v1',
+        'https://w3id.org/veres-one/v1',
+        'https://w3id.org/security/suites/ed25519-2020/v1',
+        'https://w3id.org/security/suites/x25519-2020/v1'
+      ]);
+    });
+
     it('should generate a cryptonym based DID Document', async () => {
       const {didDocument, methodFor, keyPairs} = await driver.generate();