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Fix P-256 verification in demo client #49

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Merged
iinuwa merged 1 commit into from
Jul 3, 2025
Merged

Fix P-256 verification in demo client #49

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6 changes: 4 additions & 2 deletions demo_client/webauthn.py
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Original file line number Diff line number Diff line change
Expand Up @@ -405,12 +405,14 @@ def _cose_verify(cose_key: bytes, signature: bytes, data: bytes):

cose_crv = cred_pub_key[COSE_EC2_CRV]
if cose_crv == COSE_CRV_P256:
crv = ec.SECP2561R1
crv = ec.SECP256R1()
alg = ec.ECDSA(hashes.SHA256())
else:
raise Exception(f"Unsupported COSE ECDSA curve specified: {crv}")

signing_key = ec.EllipticCurvePublicNumbers(crv, x, y).public_key()
# WebAuthn uses uncompressed points only.
pub_key_bytes = bytes(b'\x04' + x + y)
signing_key = ec.EllipticCurvePublicKey.from_encoded_point(crv, pub_key_bytes)
signing_key.verify(signature, data, alg)
elif cose_alg == COSE_ALG_EDDSA:
if kty != COSE_KTY_OKP:
Expand Down