internal void Validate(U2fResponse<U2fRegisterResponseData> response, string origin, string challenge)
{
if (response.Type != "u2f_register_response"
|| response.ResponseData.Version != "U2F_V2"
|| response.ResponseData.AppId != origin
|| response.ResponseData.Challenge != challenge
|| response.ResponseData.ClientData.Typ != "navigator.id.finishEnrollment"
|| response.ResponseData.ClientData.Challenge != challenge
|| response.ResponseData.ClientData.Origin != origin
|| response.ResponseData.ClientData.CId_PubKey != ""
|| response.ResponseData.RegistrationData.ReservedByte != 5
|| response.ResponseData.RegistrationData.KeyHandle.Length != 64 //NOTE: 64 is characterisation value; strictly speaking it only needs entropy
)
{
throw new ApplicationException();
}
using (var stream = new MemoryStream(response.ResponseData.RegistrationData.AttestationCertificateAndSignature, false))
{
var attestationCertificate = Certificate.Load(stream);
attestationCertificate.ThrowIfChainNotOkay(RootCertificates.Yubico);
var signature = stream.ToArray().Skip((int) stream.Position).ToArray();
attestationCertificate.PublicKey.ThrowIfSignatureNotOkay(signature,
new byte[] { 0 },
Hash.String(origin),
Hash.Array(response.ResponseData.ClientData.Raw),
response.ResponseData.RegistrationData.KeyHandle,
response.ResponseData.RegistrationData.UserPublicKey);
}
}
internal void Validate(U2fResponse<U2fSignResponseData> response, string origin, byte[] userPublicKey, byte[] keyHandle, string challenge, uint counter)
{
if (response.Type != "u2f_sign_response"
|| !response.ResponseData.KeyHandle.SequenceEqual(keyHandle)
|| response.ResponseData.ClientData.Typ != "navigator.id.getAssertion"
|| response.ResponseData.ClientData.Challenge != challenge
|| response.ResponseData.ClientData.Origin != origin
|| response.ResponseData.ClientData.CId_PubKey != ""
|| response.ResponseData.SignatureData.UserPresenceByte != 1
|| response.ResponseData.SignatureData.CounterValue != counter
)
{
throw new ApplicationException();
}
EllipticCurve.LoadPublicKey(userPublicKey).ThrowIfSignatureNotOkay(response.ResponseData.SignatureData.Signature,
Hash.String(origin),
new[] { response.ResponseData.SignatureData.UserPresenceByte },
response.ResponseData.SignatureData.CounterBytes,
Hash.Array(response.ResponseData.ClientData.Raw));
}
