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 def generate_did_controller_key(): return didkit.generate_ed25519_key() def keydid_from_controller_key(key): return didkit.key_to_did("key", key) def resolve_did(keydid): async def inner(): return await didkit.resolve_did(keydid, "{}") return asyncio.run(inner()) def webdid_from_controller_key(key): """ Se siguen los pasos para generar un webdid a partir de un keydid. Documentado en la docu de spruceid. """ keydid = keydid_from_controller_key(key) # "did:key:<...>" pubkeyid = keydid.rsplit(":")[-1] # <...> 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" # Reemplazamos los campos del documento DID necesarios: document["id"] = webdid_url document["verificationMethod"][0]["id"] = webdid_url_owner document["verificationMethod"][0]["controller"] = webdid_url document["authentication"][0] = webdid_url_owner document["assertionMethod"][0] = webdid_url_owner document_fixed_serialized = json.dumps(document) return webdid_url, document_fixed_serialized def generate_generic_vc_id(): # TODO agree on a system for Verifiable Credential IDs return "https://pangea.org/credentials/42" def render_and_sign_credential(vc_template: jinja2.Template, jwk_issuer, vc_data: dict[str, str]): """ Populates a VC template with data for issuance, and signs the result with the provided key. The `vc_data` parameter must at a minimum include: * issuer_did * subject_did * vc_id and must include whatever other fields are relevant for the vc_template to be instantiated. The following field(s) will be auto-generated if not passed in `vc_data`: * issuance_date (to `datetime.datetime.now()`) """ async def inner(): unsigned_vc = vc_template.render(vc_data) signed_vc = await didkit.issue_credential( unsigned_vc, '{"proofFormat": "ldp"}', jwk_issuer ) return signed_vc if vc_data.get("issuance_date") is None: vc_data["issuance_date"] = datetime.datetime.now().replace(microsecond=0).isoformat() return asyncio.run(inner()) def sign_credential(unsigned_vc: str, jwk_issuer): """ Signs the unsigned credential with the provided key. The credential template must be rendered with all user data. """ async def inner(): signed_vc = await didkit.issue_credential( unsigned_vc, '{"proofFormat": "ldp"}', jwk_issuer ) return signed_vc return asyncio.run(inner()) def verify_credential(vc): """ Returns a (bool, str) tuple indicating whether the credential is valid. If the boolean is true, the credential is valid and the second argument can be ignored. If it is false, the VC is invalid and the second argument contains a JSON object with further information. """ async def inner(): str_res = await didkit.verify_credential(vc, '{"proofFormat": "ldp"}') res = literal_eval(str_res) ok = res["warnings"] == [] and res["errors"] == [] return ok, str_res 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].encode('utf-8') ) ) ) 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: async def inner(): unsigned_vp = vp_template.render(data) signed_vp = await didkit.issue_presentation( unsigned_vp, '{"proofFormat": "ldp"}', jwk_holder ) return signed_vp data = { "holder_did": holder_did, "verifiable_credential_list": "[" + ",".join(vc_list) + "]" } return asyncio.run(inner()) def create_verifiable_presentation(jwk_holder: str, unsigned_vp: str) -> str: async def inner(): signed_vp = await didkit.issue_presentation( unsigned_vp, '{"proofFormat": "ldp"}', jwk_holder ) return signed_vp return asyncio.run(inner()) def verify_presentation(vp): """ Returns a (bool, str) tuple indicating whether the credential is valid. If the boolean is true, the credential is valid and the second argument can be ignored. If it is false, the VC is invalid and the second argument contains a JSON object with further information. """ async def inner(): proof_options = '{"proofFormat": "ldp"}' return await didkit.verify_presentation(vp, proof_options) return asyncio.run(inner())