RS256

[dscreve]

Hello,

Windows Hello requires RS256 algorithm support. Is there any plan to add it ?

David

[dscreve]

Actually, code is commented...Is there any reason why it is not implemented :

func verify(signature: Data, data: Data) throws {
throw WebAuthnError.unsupported
// let rsaSignature = _RSA.Signing.RSASignature(derRepresentation: signature)

    // var rsaPadding: _RSA.Signing.Padding
    // switch algorithm {
    // case .algRS1, .algRS256, .algRS384, .algRS512:
    //     rsaPadding = .insecurePKCS1v1_5
    // case .algPS256, .algPS384, .algPS512:
    //     rsaPadding = .PSS
    // default:
    //     throw WebAuthnError.unsupportedCOSEAlgorithmForRSAPublicKey
    // }

    // guard try _RSA.Signing.PublicKey(rawRepresentation: rawRepresentation).isValidSignature(
    //     rsaSignature,
    //     for: data,
    //     padding: rsaPadding
    // ) else {
    //     throw WebAuthnError.invalidSignature
    // }
}

[dimitribouniol]

I think it was just untested at the time (or CryptoKit didn’t make supporting RSA easy since it’s considered a non-recommended technology). You are welcome to bring support up to snuff if you are able to validate it with your system though!

[dscreve]

Ok, I will try to setup a windows system to test it

[0xTim]

Correct yes, RSA support has only been added relatively recently to Crypto Extras, so it was added as a placeholder.

[dscreve]

Pull request #87 done.