refactor verification and signed presentations
This commit is contained in:
Cayo Puigdefabregas
parent
a9cca75323
commit
8ebd824bed
2
sign.py
2
sign.py
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@ -62,3 +62,5 @@ def sign_proof(document, proof, key):
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jws = detached_sign_unencoded_payload(message, key)
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proof["jws"] = jws.decode('utf-8')[:-2]
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return proof
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202
sign_vp.py
202
sign_vp.py
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@ -1,160 +1,22 @@
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import sys
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import json
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import hashlib
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import multicodec
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import multiformats
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import nacl.signing
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import nacl.encoding
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import argparse
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from pyld import jsonld
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from jwcrypto import jwk
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from nacl.public import PublicKey
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from nacl.signing import SigningKey
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from collections import OrderedDict
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from nacl.encoding import RawEncoder
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from datetime import datetime, timezone
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from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives.asymmetric import ec
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
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# For signature
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from pyld.jsonld import JsonLdProcessor
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_debug = False
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def now():
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timestamp = datetime.now(timezone.utc).replace(microsecond=0)
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formatted_timestamp = timestamp.strftime("%Y-%m-%dT%H:%M:%SZ")
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return formatted_timestamp
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def key_to_did(key):
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"""did-key-format :=
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did:key:MULTIBASE(base58-btc, MULTICODEC(public-key-type, raw-public-key-bytes))"""
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verify_key = key.verify_key
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public_key_bytes = verify_key.encode()
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mc = multicodec.add_prefix('ed25519-pub', public_key_bytes)
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# Multibase encode the hashed bytes
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did = multiformats.multibase.encode(mc, 'base58btc')
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return f"did:key:{did}"
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def key_save(key):
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# Save the private JWK to a file
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private_jwk = key.export()
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with open('keypairs.jwk', 'w') as f:
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f.write(private_jwk)
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def key_read():
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# Save the private JWK to a file
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with open('keypairs.jwk', 'r') as f:
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private_jwk = f.read()
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return jwk.JWK.from_json(private_jwk)
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def sign_bytes(data, secret):
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return secret.sign(data)[:-len(data)]
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def sign_bytes_b64(data, key):
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signature = sign_bytes(data, key)
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sig_b64 = nacl.encoding.URLSafeBase64Encoder.encode(signature)
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return sig_b64
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def detached_sign_unencoded_payload(payload, key):
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header = b'{"alg":"EdDSA","crit":["b64"],"b64":false}'
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header_b64 = nacl.encoding.URLSafeBase64Encoder.encode(header)
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signing_input = header_b64 + b"." + payload
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sig_b64 = sign_bytes_b64(signing_input, key)
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jws = header_b64 + b".." + sig_b64
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return jws
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def urdna2015_normalize(document, proof):
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doc_dataset = jsonld.compact(document, "https://www.w3.org/2018/credentials/v1")
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sigopts_dataset = jsonld.compact(proof, "https://w3id.org/security/v2")
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doc_normalized = jsonld.normalize(
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doc_dataset,
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{'algorithm': 'URDNA2015', 'format': 'application/n-quads'}
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)
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sigopts_normalized = jsonld.normalize(
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sigopts_dataset,
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{'algorithm': 'URDNA2015', 'format': 'application/n-quads'}
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)
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return doc_normalized, sigopts_normalized
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def sha256_normalized(doc_normalized, sigopts_normalized):
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doc_digest = hashlib.sha256(doc_normalized.encode('utf-8')).digest()
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sigopts_digest = hashlib.sha256(sigopts_normalized.encode('utf-8')).digest()
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message = sigopts_digest + doc_digest
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return message
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def to_jws_payload(document, proof):
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doc_normalized, sigopts_normalized = urdna2015_normalize(document, proof)
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return sha256_normalized(doc_normalized, sigopts_normalized)
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def sign_proof(document, proof, key):
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message = to_jws_payload(document, proof)
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jws = detached_sign_unencoded_payload(message, key)
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proof["jws"] = jws.decode('utf-8')[:-2]
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return proof
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def get_presentation(vc):
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template = {
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"@context": ["https://www.w3.org/2018/credentials/v1"],
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"id": "http://example.org/presentations/3731",
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"type": ["VerifiablePresentation"],
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"holder": "",
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"verifiableCredential": []
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}
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template["verifiableCredential"].append(json.loads(vc))
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return template
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def get_keys(path_file=None):
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if path_file:
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key = key_read(path_file)
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else:
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key = jwk.JWK.generate(kty='OKP', crv='Ed25519')
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key['kid'] = 'Generated'
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jwk_pr = key.export_private(True)
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private_key_material_str = jwk_pr['d']
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missing_padding = len(private_key_material_str) % 4
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if missing_padding:
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private_key_material_str += '=' * (4 - missing_padding)
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private_key_material = nacl.encoding.URLSafeBase64Encoder.decode(private_key_material_str)
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signing_key = SigningKey(private_key_material, encoder=RawEncoder)
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return signing_key
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from utils import now
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from templates import presentation_tmpl, proof_tmpl
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from did import key_read, generate_did, get_signing_key
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from sign import sign_proof
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def sign_vp(signing_key, holder_did, vc):
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presentation = get_presentation(vc)
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_did = holder_did + "#" + holder_did.split("did:key:")[1]
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presentation = presentation_tmpl.copy()
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presentation["verifiableCredential"].append(json.loads(vc))
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presentation["holder"] = holder_did
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proof = {
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'@context':'https://w3id.org/security/v2',
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'type': 'Ed25519Signature2018',
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'proofPurpose': 'assertionMethod',
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'verificationMethod': _did,
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'created': now()
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}
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_did = holder_did + "#" + holder_did.split("did:key:")[1]
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proof = proof_tmpl.copy()
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proof['verificationMethod'] = _did
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proof['created'] = now()
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sign_proof(presentation, proof, signing_key)
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del proof['@context']
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presentation['proof'] = proof
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@ -162,31 +24,27 @@ def sign_vp(signing_key, holder_did, vc):
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def main():
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path_credential = None
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path_keys = None
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parser=argparse.ArgumentParser(description='Generates a new credential')
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parser.add_argument("-k", "--key-path", required=True)
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parser.add_argument("-c", "--credential-path", required=True)
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args=parser.parse_args()
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if len(sys.argv) > 1:
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path_credential = sys.argv[1]
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if args.key_path and args.credential_path:
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with open(args.credential_path, "r") as f:
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vc = f.read()
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if not vc:
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print("You need pass a credential.")
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return
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key = key_read(args.key_path)
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did = generate_did(key)
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signing_key = get_signing_key(key)
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vp = sign_vp(signing_key, did, vc)
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print(json.dumps(vp, separators=(',', ':')))
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if not path_credential:
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print("You need pass a credential.")
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return
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if len(sys.argv) > 2:
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path_keys = sys.argv[2]
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with open(path_credential, "r") as f:
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vc = f.read()
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if not vc:
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print("You need pass a credential.")
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return
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signing_key = get_keys(path_keys)
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holder_did = key_to_did(signing_key)
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vp = sign_vp(signing_key, holder_did, vc)
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print(json.dumps(vp, separators=(',', ':')))
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if __name__ == "__main__":
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main()
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@ -0,0 +1,67 @@
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import json
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import nacl.encoding
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import nacl.signing
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import multicodec
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import multiformats
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from nacl.signing import VerifyKey
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from sign import to_jws_payload
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def get_signing_input(payload):
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header = b'{"alg":"EdDSA","crit":["b64"],"b64":false}'
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header_b64 = nacl.encoding.URLSafeBase64Encoder.encode(header)
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signing_input = header_b64 + b"." + payload
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return header_b64, signing_input
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def get_message(vc):
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document = vc.copy()
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proof = document.pop("proof", {})
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jws = proof.pop("jws", None)
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proof['@context'] = 'https://w3id.org/security/v2'
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if not jws:
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return None, False
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return jws+"==", to_jws_payload(document, proof)
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def get_verify_key(vc):
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did = vc["proof"]["verificationMethod"].split("#")[0]
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pub = did.split(":")[-1]
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mc = multiformats.multibase.decode(pub)
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public_key_bytes = multicodec.remove_prefix(mc)
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return VerifyKey(public_key_bytes)
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def jws_split(jws):
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header, sig_b64 = jws.split("..")
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signature = nacl.encoding.URLSafeBase64Encoder.decode(sig_b64.encode())
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return header.encode(), signature
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def verify_vc(credential):
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vc = json.loads(credential)
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header = {"alg": "EdDSA", "crit": ["b64"], "b64": False}
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jws, message = get_message(vc)
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if not message:
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return False
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header_b64, signature = get_signing_input(message)
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header_jws, signature_jws = jws_split(jws)
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if header_jws != header_b64:
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return False
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header_jws_json = json.loads(
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nacl.encoding.URLSafeBase64Encoder.decode(header_jws)
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)
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for k, v in header.items():
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if header_jws_json.get(k) != v:
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return False
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verify_key = get_verify_key(vc)
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data_verified = verify_key.verify(signature_jws+signature)
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return data_verified == signature
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135
verify_vc.py
135
verify_vc.py
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@ -1,129 +1,22 @@
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import sys
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import json
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import hashlib
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import multicodec
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import multiformats
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import nacl.signing
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import nacl.encoding
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from pyld import jsonld
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from jwcrypto import jwk
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from nacl.signing import SigningKey, VerifyKey
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from collections import OrderedDict
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from nacl.encoding import RawEncoder
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from datetime import datetime, timezone
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from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives.asymmetric import ec
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
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def key_to_did(public_key_bytes):
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"""did-key-format :=
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did:key:MULTIBASE(base58-btc, MULTICODEC(public-key-type, raw-public-key-bytes))"""
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mc = multicodec.add_prefix('ed25519-pub', public_key_bytes)
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# Multibase encode the hashed bytes
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did = multiformats.multibase.encode(mc, 'base58btc')
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return f"did:key:{did}"
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def get_signing_input(payload):
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header = b'{"alg":"EdDSA","crit":["b64"],"b64":false}'
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header_b64 = nacl.encoding.URLSafeBase64Encoder.encode(header)
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signing_input = header_b64 + b"." + payload
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return header_b64, signing_input
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def urdna2015_normalize(document, proof):
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doc_dataset = jsonld.compact(document, "https://www.w3.org/2018/credentials/v1")
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sigopts_dataset = jsonld.compact(proof, "https://w3id.org/security/v2")
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doc_normalized = jsonld.normalize(
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doc_dataset,
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{'algorithm': 'URDNA2015', 'format': 'application/n-quads'}
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)
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sigopts_normalized = jsonld.normalize(
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sigopts_dataset,
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{'algorithm': 'URDNA2015', 'format': 'application/n-quads'}
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)
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return doc_normalized, sigopts_normalized
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def sha256_normalized(doc_normalized, sigopts_normalized):
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doc_digest = hashlib.sha256(doc_normalized.encode('utf-8')).digest()
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sigopts_digest = hashlib.sha256(sigopts_normalized.encode('utf-8')).digest()
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message = sigopts_digest + doc_digest
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return message
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def to_jws_payload(document, proof):
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doc_normalized, sigopts_normalized = urdna2015_normalize(document, proof)
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return sha256_normalized(doc_normalized, sigopts_normalized)
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def get_message(vc):
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document = vc.copy()
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proof = document.pop("proof", {})
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jws = proof.pop("jws", None)
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proof['@context'] = 'https://w3id.org/security/v2'
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if not jws:
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return None, False
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return jws+"==", to_jws_payload(document, proof)
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def get_verify_key(vc):
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did = vc["proof"]["verificationMethod"].split("#")[0]
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pub = did.split(":")[-1]
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mc = multiformats.multibase.decode(pub)
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public_key_bytes = multicodec.remove_prefix(mc)
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return VerifyKey(public_key_bytes)
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def jws_split(jws):
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header, sig_b64 = jws.split("..")
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signature = nacl.encoding.URLSafeBase64Encoder.decode(sig_b64.encode())
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return header.encode(), signature
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def verify_vc(vc):
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header = {"alg": "EdDSA", "crit": ["b64"], "b64": False}
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jws, message = get_message(vc)
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if not message:
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return False
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header_b64, signature = get_signing_input(message)
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header_jws, signature_jws = jws_split(jws)
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if header_jws != header_b64:
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return False
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header_jws_json = json.loads(
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nacl.encoding.URLSafeBase64Encoder.decode(header_jws)
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)
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for k, v in header.items():
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if header_jws_json.get(k) != v:
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return False
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verify_key = get_verify_key(vc)
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data_verified = verify_key.verify(signature_jws+signature)
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return data_verified == signature
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import argparse
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from verify import verify_vc
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def get_credential(path_credential):
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with open(path_credential, "r") as f:
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vc = f.read()
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return json.loads(vc)
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return vc
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def main():
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parser=argparse.ArgumentParser(description='Verify a credential')
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parser.add_argument("credential_path")
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args=parser.parse_args()
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if args.credential_path:
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credential = get_credential(args.credential_path)
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print(verify_vc(credential))
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if __name__ == "__main__":
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if len(sys.argv) > 1:
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path_credential = sys.argv[1]
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credential = get_credential(path_credential)
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print(verify_vc(credential))
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else:
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print("You need pass a credential.")
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main()
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