resolve conflicts

idhub/models.py

@@ -440,6 +440,7 @@ class DID(models.Model):
         related_name='dids',
         null=True,
     )
+    # JSON-serialized DID document
     didweb_document = models.TextField()
 
     def get_key_material(self, password):
@@ -589,6 +590,7 @@ class VerificableCredential(models.Model):
         on_delete=models.CASCADE,
         related_name='vcredentials',
     )
+    revocationBitmapIndex = models.AutoField()
 
     def get_data(self, password):
         if not self.data:

idhub/views.py

@@ -1,6 +1,10 @@
+import base64
+import json
 import uuid
 import logging
+import zlib
 
+import pyroaring
 from django.conf import settings
 from django.core.cache import cache
 from django.urls import reverse_lazy
@@ -12,7 +16,7 @@ from django.shortcuts import get_object_or_404, redirect
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.http import HttpResponseRedirect, HttpResponse, Http404
 
-from idhub.models import DID
+from idhub.models import DID, VerificableCredential
 from idhub.email.views import NotifyActivateUserByEmail
 from trustchain_idhub import settings
 
@@ -99,9 +103,29 @@ class PasswordResetView(auth_views.PasswordResetView):
 
 
 def serve_did(request, did_id):
-    id_did = f'did:web:{settings.DOMAIN}:did-registry:{did_id}'
+    import urllib.parse
+    domain = urllib.parse.urlencode({"domain": settings.DOMAIN})[7:]
+    id_did = f'did:web:{domain}:did-registry:{did_id}'
     did = get_object_or_404(DID, did=id_did)
-    document = did.didweb_document
+    # Deserialize the base DID from JSON storage
+    document = json.loads(did.didweb_document)
+    # Has this DID issued any Verifiable Credentials? If so, we need to add a Revocation List "service"
+    #  entry to the DID document.
+    revoked_credentials = did.vcredentials.filter(status=VerificableCredential.Status.REVOKED)
+    revoked_credential_indexes = []
+    for credential in revoked_credentials:
+        revoked_credential_indexes.append(credential.revocationBitmapIndex)
+    # TODO: Conditionally add "service" to DID document only if the DID has issued any VC
+    revocation_bitmap = pyroaring.BitMap(revoked_credential_indexes)
+    encoded_revocation_bitmap = base64.b64encode(zlib.compress(revocation_bitmap.serialize()))
+    revocation_service = [{  # This is an object within a list.
+        "id": f"{id_did}#revocation",
+        "type": "RevocationBitmap2022",
+        "serviceEndpoint": f"data:application/octet-stream;base64,{encoded_revocation_bitmap}"
+    }]
+    document["service"] = revocation_service
+    # Serialize the DID + Revocation list in preparation for sending
+    document = json.dumps(document)
     retval = HttpResponse(document)
     retval.headers["Content-Type"] = "application/json"
     return retval

requirements.txt

@@ -30,3 +30,4 @@ ujson==5.9.0
 openpyxl==3.1.2
 jsonpath_ng==1.6.1
 ./didkit-0.3.2-cp311-cp311-manylinux_2_34_x86_64.whl
+pyroaring==0.4.5

utils/idhub_ssikit/__init__.py

@@ -1,11 +1,16 @@
 import asyncio
+import base64
 import datetime
+import zlib
+from ast import literal_eval
+
 import didkit
 import json
 import urllib
 import jinja2
 from django.template.backends.django import Template
 from django.template.loader import get_template
+from pyroaring import BitMap
 
 from trustchain_idhub import settings
 
@@ -18,9 +23,12 @@ def keydid_from_controller_key(key):
     return didkit.key_to_did("key", key)
 
 
-async def resolve_keydid(keydid):
+def resolve_did(keydid):
+    async def inner():
         return await didkit.resolve_did(keydid, "{}")
 
+    return asyncio.run(inner())
+
 
 def webdid_from_controller_key(key):
     """
@@ -29,7 +37,7 @@ def webdid_from_controller_key(key):
     """
     keydid = keydid_from_controller_key(key)  # "did:key:<...>"
     pubkeyid = keydid.rsplit(":")[-1]  # <...>
-    document = json.loads(asyncio.run(resolve_keydid(keydid)))  # Documento DID en terminos "key"
+    document = json.loads(resolve_did(keydid))  # Documento DID en terminos "key"
     domain = urllib.parse.urlencode({"domain": settings.DOMAIN})[7:]
     webdid_url = f"did:web:{domain}:did-registry:{pubkeyid}"  # nueva URL: "did:web:idhub.pangea.org:<...>"
     webdid_url_owner = webdid_url + "#owner"
@@ -99,9 +107,37 @@ def verify_credential(vc):
     If it is false, the VC is invalid and the second argument contains a JSON object with further information.
     """
     async def inner():
-        return await didkit.verify_credential(vc, '{"proofFormat": "ldp"}')
+        str_res = await didkit.verify_credential(vc, '{"proofFormat": "ldp"}')
+        res = literal_eval(str_res)
+        ok = res["warnings"] == [] and res["errors"] == []
+        return ok, str_res
 
-    return asyncio.run(inner())
+    valid, reason = asyncio.run(inner())
+    if not valid:
+        return valid, reason
+    # Credential passes basic signature verification. Now check it against its schema.
+    # TODO: check agasint schema
+    pass
+    # Credential verifies against its schema. Now check revocation status.
+    vc = json.loads(vc)
+    if "credentialStatus" in vc:
+        revocation_index = int(vc["credentialStatus"]["revocationBitmapIndex"])  # NOTE: THIS FIELD SHOULD BE SERIALIZED AS AN INTEGER, BUT IOTA DOCUMENTAITON SERIALIZES IT AS A STRING. DEFENSIVE CAST ADDED JUST IN CASE.
+        vc_issuer = vc["issuer"]["id"]  # This is a DID
+        if vc_issuer[:7] == "did:web":  # Only DID:WEB can revoke
+            issuer_did_document = json.loads(resolve_did(vc_issuer))  # TODO: implement a caching layer so we don't have to fetch the DID (and thus the revocation list) every time a VC is validated.
+            issuer_revocation_list = issuer_did_document["service"][0]
+            assert issuer_revocation_list["type"] == "RevocationBitmap2022"
+            revocation_bitmap = BitMap.deserialize(
+                zlib.decompress(
+                    base64.b64decode(
+                        issuer_revocation_list["serviceEndpoint"].rsplit(",")[1]
+                    )
+                )
+            )
+            if revocation_index in revocation_bitmap:
+                return False, "Credential has been revoked by the issuer"
+    # Fallthrough means all is good.
+    return True, "Credential passes all checks"
 
 
 def issue_verifiable_presentation(vp_template: Template, vc_list: list[str], jwk_holder: str, holder_did: str) -> str: