Add support for includeTimestamp option.

-add 'includeTimestamp' option: if not true, 'created' field deleted from proof
-add tests for includeTimestamp option

lib/create.js

@@ -9,8 +9,9 @@ import {createVerifier} from './createVerifier.js';
 import {name} from './name.js';
 import {requiredAlgorithm} from './requiredAlgorithm.js';
 
-export function createCryptosuite({extraInformation = new Uint8Array()} = {}) {
-  const options = {extraInformation};
+export function createCryptosuite({extraInformation = new Uint8Array(),
+  includeTimestamp = false} = {}) {
+  const options = {extraInformation, includeTimestamp};
   return {
     name,
     canonize,
@@ -25,8 +26,11 @@ async function _createSignData({cryptosuite, document, proof, documentLoader}) {
   const options = {documentLoader};
 
   // delete proof timestamp
-  delete proof.created;
-
+  if(cryptosuite.options.includeTimestamp == true) {
+  } else {
+    delete proof.created;
+  }
+
   // create hash from `extraInformation`
   const hasher = createHasher();
   const externalHash = await hasher.hash(cryptosuite.options.extraInformation);

test/EcdsaXi2023Cryptosuite.spec.js

@@ -27,7 +27,8 @@ const extraInformation = new Uint8Array([
   12, 52, 75, 63, 74, 85, 21, 5, 62, 100,
   12, 52, 75, 63
 ]);
-const ecdsaXi2023Cryptosuite = createCryptosuite({extraInformation});
+const includeTimestamp = false;
+const ecdsaXi2023Cryptosuite = createCryptosuite({extraInformation, includeTimestamp});
 
 describe('EcdsaXi2023Cryptosuite', () => {
   describe('exports', () => {
@@ -150,6 +151,58 @@ describe('EcdsaXi2023Cryptosuite', () => {
       expect(error).to.not.exist;
     });
 
+    it('should contain a timestamp with includeTimestamp = true passed', async () => {
+      const unsignedCredential = JSON.parse(JSON.stringify(credential));
+      const keyPair = await EcdsaMultikey.from({...ecdsaMultikeyKeyPair});
+      const date = '2023-03-01T21:29:24Z';
+      const includeTimestamp = true;
+      const ecdsaXi2023CryptosuiteWithTimestamp = createCryptosuite({extraInformation, includeTimestamp});
+      const suite = new DataIntegrityProof({
+        signer: keyPair.signer(), date, cryptosuite: ecdsaXi2023CryptosuiteWithTimestamp
+      });
+
+      let error;
+      let signed;
+      try {
+        signed = await jsigs.sign(unsignedCredential, {
+          suite,
+          purpose: new AssertionProofPurpose(),
+          documentLoader
+        });
+      } catch(e) {
+        error = e;
+      }
+
+      expect(error).to.not.exist;
+      expect(signed).to.exist;
+      expect(signed.proof.created).to.exist;
+    });
+
+    it('should not contain a timestamp otherwise', async () => {
+      const unsignedCredential = JSON.parse(JSON.stringify(credential));
+      const keyPair = await EcdsaMultikey.from({...ecdsaMultikeyKeyPair});
+      const date = '2023-03-01T21:29:24Z';
+      const suite = new DataIntegrityProof({
+        signer: keyPair.signer(), date, cryptosuite: ecdsaXi2023Cryptosuite
+      });
+
+      let error;
+      let signed;
+      try {
+        signed = await jsigs.sign(unsignedCredential, {
+          suite,
+          purpose: new AssertionProofPurpose(),
+          documentLoader
+        });
+      } catch(e) {
+        error = e;
+      }
+
+      expect(error).to.not.exist;
+      expect(signed).to.exist;
+      expect(signed.proof.created).to.not.exist;
+    });
+
     it('should fail to sign with undefined term', async () => {
       const unsignedCredential = JSON.parse(JSON.stringify(credential));
       unsignedCredential.undefinedTerm = 'foo';

test/testSignVerify.js

@@ -38,10 +38,11 @@ const unsignedCredential = {
 const extraInformation = new Uint8Array([12, 52, 75, 63, 74, 85,
   21, 5, 62, 100]);
 
+const includeTimestamp = false;
 // create suite
 const suite = new DataIntegrityProof({
   signer: keyPair.signer(),
-  cryptosuite: createCryptosuite({extraInformation})
+  cryptosuite: createCryptosuite({extraInformation, includeTimestamp})
 });
 
 // create signed credential