C# .NET Framework 实现SM2加签、验签

本文只实现SM2的加签以及验签。
首先需要安装包 Portable.BouncyCastle。然后创建类 EasyGmutil

Code

namespace ConsoleApp1
{public class EasyGmUtil{private static X9ECParameters x9ECParameters = GMNamedCurves.GetByName("sm2p256v1");private static ECDomainParameters ecDomainParameters = new ECDomainParameters(x9ECParameters.Curve, x9ECParameters.G, x9ECParameters.N);
    /**** @param msg* @param userId* @param privateKey* @return r||s，直接拼接byte数组的rs*/public static byte[] signSm3WithSm2(byte[] msg, byte[] userId, byte[] privateKeyBytes){ECPrivateKeyParameters privateKeyParameters = getPrivatekeyFromD(new BigInteger(1, privateKeyBytes));return rsAsn1ToPlainByteArray(signSm3WithSm2Asn1Rs(msg, userId, privateKeyParameters));}/*** @param msg* @param userId* @param privateKey* @return rs in <b>asn1 format</b>*/public static byte[] signSm3WithSm2Asn1Rs(byte[] msg, byte[] userId, AsymmetricKeyParameter privateKey){try{ISigner signer = SignerUtilities.InitSigner("SM3withSM2", true, privateKey, new SecureRandom());signer.BlockUpdate(msg, 0, msg.Length);byte[] sig = signer.GenerateSignature();return sig;}catch (Exception e){return null;}}/**** @param msg* @param userId* @param rs r||s，直接拼接byte数组的rs* @param publicKey* @return

*/

public static bool verifySm3WithSm2(byte[] msg, byte[] userId, byte[] rs, byte[] publicKeyBytes)

{

if (rs == null || msg == null || userId == null) return false;

if (rs.Length != RS_LEN * 2) return false;
        if (publicKeyBytes.Length != 64 && publicKeyBytes.Length != 65) throw new ArgumentException("err key length");BigInteger x, y;if (publicKeyBytes.Length > 64){x = fromUnsignedByteArray(publicKeyBytes, 1, 32);y = fromUnsignedByteArray(publicKeyBytes, 33, 32);}else{x = fromUnsignedByteArray(publicKeyBytes, 0, 32);y = fromUnsignedByteArray(publicKeyBytes, 32, 32);}ECPublicKeyParameters publicKey = getPublickeyFromXY(x, y);return verifySm3WithSm2Asn1Rs(msg, userId, rsPlainByteArrayToAsn1(rs), publicKey);}public static BigInteger fromUnsignedByteArray(byte[] var0, int var1, int var2){byte[] var3 = var0;if (var1 != 0 || var2 != var0.Length){var3 = new byte[var2];Array.Copy(var0, var1, var3, 0, var2);}return new BigInteger(1, var3);}/**** @param msg* @param userId* @param rs in <b>asn1 format</b>* @param publicKey* @return*/public static bool verifySm3WithSm2Asn1Rs(byte[] msg, byte[] userId, byte[] sign, AsymmetricKeyParameter publicKey){try{ISigner signer = SignerUtilities.GetSigner("SM3withSM2");signer.Init(false, publicKey);signer.BlockUpdate(msg, 0, msg.Length);return signer.VerifySignature(sign);}catch (Exception e){return false;}}public static ECPrivateKeyParameters getPrivatekeyFromD(BigInteger d){return new ECPrivateKeyParameters(d, ecDomainParameters);}public static ECPublicKeyParameters getPublickeyFromXY(BigInteger x, BigInteger y){return new ECPublicKeyParameters(x9ECParameters.Curve.CreatePoint(x, y), ecDomainParameters);}private const int RS_LEN = 32;private static byte[] bigIntToFixexLengthBytes(BigInteger rOrS){// for sm2p256v1, n is 00fffffffeffffffffffffffffffffffff7203df6b21c6052b53bbf40939d54123,// r and s are the result of mod n, so they should be less than n and have length<=32byte[] rs = rOrS.ToByteArray();if (rs.Length == RS_LEN) return rs;else if (rs.Length == RS_LEN + 1 && rs[0] == 0) return Arrays.CopyOfRange(rs, 1, RS_LEN + 1);else if (rs.Length < RS_LEN){byte[] result = new byte[RS_LEN];Arrays.Fill(result, (byte)0);Buffer.BlockCopy(rs, 0, result, RS_LEN - rs.Length, rs.Length);return result;}else{throw new ArgumentException("err rs: " + Hex.ToHexString(rs));}}/*** BC的SM3withSM2签名得到的结果的rs是asn1格式的，这个方法转化成直接拼接r||s* @param rsDer rs in asn1 format* @return sign result in plain byte array*/private static byte[] rsAsn1ToPlainByteArray(byte[] rsDer){Asn1Sequence seq = Asn1Sequence.GetInstance(rsDer);byte[] r = bigIntToFixexLengthBytes(DerInteger.GetInstance(seq[0]).Value);byte[] s = bigIntToFixexLengthBytes(DerInteger.GetInstance(seq[1]).Value);byte[] result = new byte[RS_LEN * 2];Buffer.BlockCopy(r, 0, result, 0, r.Length);Buffer.BlockCopy(s, 0, result, RS_LEN, s.Length);return result;}/*** BC的SM3withSM2验签需要的rs是asn1格式的，这个方法将直接拼接r||s的字节数组转化成asn1格式* @param sign in plain byte array* @return rs result in asn1 format*/private static byte[] rsPlainByteArrayToAsn1(byte[] sign){if (sign.Length != RS_LEN * 2) throw new ArgumentException("err rs. ");BigInteger r = new BigInteger(1, Arrays.CopyOfRange(sign, 0, RS_LEN));BigInteger s = new BigInteger(1, Arrays.CopyOfRange(sign, RS_LEN, RS_LEN * 2));Asn1EncodableVector v = new Asn1EncodableVector();v.Add(new DerInteger(r));v.Add(new DerInteger(s));try{return new DerSequence(v).GetEncoded("DER");}catch (IOException e){//log.Error("RsPlainByteArrayToAsn1 error: " + e.Message, e);return null;}}
}

}

此处为签名及验签 Demo

Code

string PrivateKey = "AJciGDkPWcwX"; // 私钥，用于加签，此处是乱写的
string PublicKey = "BFaPS+Hj3eXg4ENOXDjrpLhwNIY";  // 公钥，与私钥配对，此处是乱写的
string userId = "";

string str = "TestContent";

//对字符串签名

byte[] signByte = EasyGmUtil.signSm3WithSm2(Encoding.UTF8.GetBytes(str),

Encoding.UTF8.GetBytes(userId),  Org.BouncyCastle.Utilities.Encoders.Base64.Decode(PrivateKey));

string signStr =  Org.BouncyCastle.Utilities.Encoders.Base64.ToBase64String(signByte);
//验签

bool flag = EasyGmUtil.verifySm3WithSm2(Encoding.UTF8.GetBytes(str), Encoding.UTF8.GetBytes(userId),

Org.BouncyCastle.Utilities.Encoders.Base64.Decode(signStr),

Org.BouncyCastle.Utilities.Encoders.Base64.Decode(PublicKey));