Merge pull request #256 from blockchain-certificates/feat/multiple-si…

…gnatures-non-chained

Support non chained signatures

cert_issuer/blockchain_handlers/bitcoin/__init__.py

@@ -49,12 +49,12 @@ def instantiate_blockchain_handlers(app_config, file_mode=True):
 
     if file_mode:
         certificate_batch_handler = CertificateBatchHandler(secret_manager=secret_manager,
-                                                            certificate_handler=CertificateV3Handler(),
+                                                            certificate_handler=CertificateV3Handler(app_config),
                                                             merkle_tree=MerkleTreeGenerator(),
                                                             config=app_config)
     else:
         certificate_batch_handler = CertificateBatchWebHandler(secret_manager=secret_manager,
-                                                               certificate_handler=CertificateWebV3Handler(),
+                                                               certificate_handler=CertificateWebV3Handler(app_config),
                                                                merkle_tree=MerkleTreeGenerator(),
                                                                config=app_config)
     if chain.is_mock_type():

cert_issuer/certificate_handlers.py

@@ -11,6 +11,9 @@
 
 
 class CertificateV3Handler(CertificateHandler):
+    def __init__(self, app_config):
+        self.app_config = app_config
+
     def get_byte_array_to_issue(self, certificate_metadata):
         certificate_json = self._get_certificate_to_issue(certificate_metadata)
         return JSONLDHandler.normalize_to_utf8(certificate_json)
@@ -22,7 +25,7 @@ def add_proof(self, certificate_metadata, merkle_proof):
         :return:
         """
         certificate_json = self._get_certificate_to_issue(certificate_metadata)
-        certificate_json = ProofHandler().add_proof(certificate_json, merkle_proof)
+        certificate_json = ProofHandler().add_proof(certificate_json, merkle_proof, self.app_config)
 
         with open(certificate_metadata.blockchain_cert_file_name, 'w') as out_file:
             out_file.write(json.dumps(certificate_json))
@@ -33,11 +36,14 @@ def _get_certificate_to_issue(self, certificate_metadata):
         return certificate_json
 
 class CertificateWebV3Handler(CertificateHandler):
+    def __init__(self, app_config):
+        self.app_config = app_config
+
     def get_byte_array_to_issue(self, certificate_json):
         return JSONLDHandler.normalize_to_utf8(certificate_json)
 
     def add_proof(self, certificate_json, merkle_proof):
-        certificate_json = ProofHandler().add_proof(certificate_json, merkle_proof)
+        certificate_json = ProofHandler().add_proof(certificate_json, merkle_proof, self.app_config)
         return certificate_json
 
 class CertificateBatchWebHandler(BatchHandler):

cert_issuer/config.py

@@ -114,6 +114,18 @@ def add_arguments(p):
                    env_var='CONTEXT_FILE_PATHS',
                    nargs='+'
                    )
+    p.add_argument('--multiple_proofs',
+                   default='chained',
+                   type=str,
+                   choices=['chained', 'concurrent'],
+                   help='How to handle a document that was previously signed by another party. \n' +
+                        'If the document has not been signed yet, a single proof will be added. \n' +
+                        '"chained": Chained proof also sign the previous proof(s) of the document, making them ' +
+                        'untemperable with in the final document, ie: a notary signs over the signatures of the buyer ' +
+                        'and the seller in a real estate transaction. \n' +
+                        '"concurrent": Concurrent proofs mean the parties independently sign the document without ' +
+                        'the other parties\' signatures. Defaults to chained proofs.'
+    )
 
 
 def get_config():

cert_issuer/proof_handler.py

@@ -6,20 +6,31 @@ class ProofHandler:
     def __init__(self):
         self.contextUrls = ContextUrls()
 
-    def add_proof(self, certificate_json, merkle_proof):
+    def add_proof(self, certificate_json, merkle_proof, app_config=None):
         if 'proof' in certificate_json:
             if not isinstance(certificate_json['proof'], list):
                 # convert proof to list
                 initial_proof = certificate_json['proof']
                 certificate_json['proof'] = [initial_proof]
-            previous_proof = certificate_json['proof'][-1]
-            certificate_json['proof'].append(ChainedProof2021(previous_proof, merkle_proof).to_json_object())
-            self.update_context_for_chained_proof(certificate_json)
+            if self.is_multiple_proof_config_chained(app_config):
+                self.add_chained_proof(certificate_json, merkle_proof)
+            else:
+                certificate_json['proof'].append(merkle_proof)
         else:
             certificate_json['proof'] = merkle_proof
             self.update_context_for_single_proof(certificate_json)
         return certificate_json
 
+    def is_multiple_proof_config_chained(self, app_config):
+        if app_config is None:
+            return True
+        return app_config.multiple_proofs == 'chained'
+
+    def add_chained_proof(self, certificate_json, merkle_proof):
+        previous_proof = certificate_json['proof'][-1]
+        certificate_json['proof'].append(ChainedProof2021(previous_proof, merkle_proof).to_json_object())
+        self.update_context_for_chained_proof(certificate_json)
+
     def update_context_for_chained_proof(self, certificate_json):
         context = certificate_json['@context']
         if self.contextUrls.merkle_proof_2019() not in context:

tests/test_certificate_handler.py

@@ -189,7 +189,7 @@ def xtest_add_proof(self, mock_open):
         assert file_call in call_strings
 
     def test_web_add_proof(self):
-        handler = CertificateWebV3Handler()
+        handler = CertificateWebV3Handler(None)
         proof = {'a': 'merkel'}
         chain = mock.Mock()
         certificate_json = {

tests/test_proof_handler.py

@@ -43,6 +43,38 @@ def test_single_signature_3_1_update_context_merkle_proof_2019(self):
         output = self.handler.add_proof(fixture_certificate_json, fixture_proof)
         self.assertIn(self.contextUrls.merkle_proof_2019(), output['@context'])
 
+    def test_multiple_non_chained_signature(self):
+        fixture_initial_proof = {
+          'type': 'Ed25519Signature2020',
+          'created': '2022-05-02T16:36:22.933Z',
+          'verificationMethod': 'did:key:z6MkjHnntGvtLjwfAMHWTAXXGJHhVL3DPtaT9BHmyTjWpjqs#z6MkjHnntGvtLjwfAMHWTAXXGJHhVL3DPtaT9BHmyTjWpjqs',
+          'proofPurpose': 'assertionMethod',
+          'proofValue': 'zAvFt59599JweBZ4zPP6Ge8LhKgECtBvDRmjG5VQbgEkPCiyMcM9QAPanJgSCs6RRGcKu96qNpfmpe9eTygpFZP6'
+        }
+        fixture_certificate_json = {
+            '@context': [
+                'https://www.w3.org/2018/credentials/v1',
+                'https://w3id.org/blockcerts/v3'
+            ],
+            'kek': 'kek',
+            'proof': fixture_initial_proof
+        }
+        fixture_proof = {
+            'type': 'MerkleProof2019',
+            'created': '2022-05-05T08:05:14.912828',
+            'proofValue': 'zMcm4LfQFUZkWZyLJp1bqtXF8vkZZwp79x7Nvt5BmN2XV4usLLtDoeqiq3et923mcWfXde4a3m4f57yUZcATCbBXV1byb5AXbV8EzT6E8B9JKf3scvxxZCBVePtV4SrhYysAiLNJ9N2R8LgnpJ47wnQHkaTB1AMxrcLEHUTxm4zJTtQqf9orDLf3L4VoLzmST7ZzsDjuX9cw2hZ3Aazhhjy7swG44xfF1PC73SyCv77pDnJ6BSHm3azmbVG6BXv1EPtwF4J1YRqwojBEWk9nDgduACR7b9qNhQ46ND4B5vL8p3LkqTh',
+            'proofPurpose': 'assertionMethod',
+            'verificationMethod': 'did:ion:EiA_Z6LQILbB2zj_eVrqfQ2xDm4HNqeJUw5Kj2Z7bFOOeQ#key-1'
+        }
+        class MockConfig:
+            multiple_proofs = 'concurrent'
+
+        output = self.handler.add_proof(fixture_certificate_json, fixture_proof, MockConfig())
+        self.assertEqual(output['proof'], [
+            fixture_initial_proof,
+            fixture_proof
+        ])
+
     def test_multiple_two_chained_signature(self):
         fixture_initial_proof = {
           'type': 'Ed25519Signature2020',