C# How ro get X509 PublicKey from byte stream

问题

Trying to get X509 PublicKey from byte stream using this code.

[Fact]
public void CreatePublicKeyParameters__ShouldReturnPublicKey__WhenPassPublicKeyBytes()
{
    ApplePay applePay = new ApplePay(new MOBSHOPApplePayRequest());
    byte[] privateKey = Base64.Decode("MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgjyo3fzxT7j+CFxC7I4B5iVee2FUyn2vfOSjcgp2/g6qhRANCAARdoBFEtnuapXFKw4DYWsW0yV4bavpdWKszkefi19AhlIRE3WSNWSn25W5tZNFjMWtLISBmqANyufx2xP19oRvy");
    var publickey = applePay.CreatePublicKeyParameters(privateKey);
}

public AsymmetricKeyParameter CreatePublicKeyParameters(byte[] ephemeralPublicKeyBytes)
{
      return (ECPublicKeyParameters)PublicKeyFactory.CreateKey(ephemeralPublicKeyBytes);
}

Getting following error

Bad sequence size: 3
Parameter name: seq

BouncyCastle.Crypto

at Org.BouncyCastle.Asn1.X509.SubjectPublicKeyInfo..ctor(Asn1Sequence seq)
at Org.BouncyCastle.Asn1.X509.SubjectPublicKeyInfo.GetInstance(Object obj)
at Org.BouncyCastle.Security.PublicKeyFactory.CreateKey(Byte[] keyInfoData)

Basically, I'm trying to convert this following JAVA code to C#

public ECPublicKey CreatePublicKeyParameters(byte[] ephemeralPublicKeyBytes)
    {
    KeyFactory keyFactory = KeyFactory.getInstance( "ECDH", "BC" );
    X509EncodedKeySpec encodedKeySpec = new X509EncodedKeySpec( ephemeralPublicKeyBytes );
    ECPublicKey ephemeralPublicKey = (ECPublicKey) keyFactory.generatePublic( encodedKeySpec );
    return ECPublicKey
    }

Please help me.

回答1:

Sorry, it was wrong test input data. It's working with this below testcase.

 [Fact]
        public void CreatePublicKeyParameters__ShouldReturnPublicKey__WhenPassPublicKeyBytes()
        {

            ApplePay applePay = new ApplePay(new MOBSHOPApplePayRequest());
            byte[] privateKey = Base64.Decode(
                "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEl/XAbOgrSCupps/QbIxJ3u4QZ1PlbO5uGDD1zj/JGMoephYSEgw+63gHQHekx3T8duXN3CoYafUpuQlwOeK6/w==");
            var publickey = applePay.CreatePublicKeyParameters(privateKey);
        }

Thanks

来源：https://stackoverflow.com/questions/39810964/c-sharp-how-ro-get-x509-publickey-from-byte-stream

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