public static bool VerifyPublickey(string pub_x, string pub_y, string curve = "")
{
pub_x = xTool.ConvertTool.RemoveSpace(pub_x);
pub_y = xTool.ConvertTool.RemoveSpace(pub_y);
ECDSABase ecdsa = new ECDSABase(new ECCurve(curve));
BigInteger x = BigInteger.Parse("00" + pub_x, System.Globalization.NumberStyles.AllowHexSpecifier);
BigInteger y = BigInteger.Parse("00" + pub_y, System.Globalization.NumberStyles.AllowHexSpecifier);
ECPoint p = new ECPoint(x, y);
if (ECCMath.IsInfinityPoint(p))
{
return(false);
}
if (!ECCMath.RangeBetween(x, BigInteger.One, ECCurve.p - 1))
{
return(false);
}
if (!ECCMath.RangeBetween(y, BigInteger.One, ECCurve.p - 1))
{
return(false);
}
if (!ECCMath.IsOnCurve(p))
{
return(false);
}
ECPoint O = ECCMath.ScalarMult(ECCurve.n, p);
if (!ECCMath.IsInfinityPoint(O))
{
return(false);
}
//throw new Exception("O is NOT Infinity Point");
return(true);
}
public static string Decrypt(string privateKey, string data)
{
privateKey = xTool.ConvertTool.RemoveSpace(privateKey);
data = xTool.ConvertTool.RemoveSpace(data);
if (data.Length % 2 != 0)
{
throw new Exception("Invalid Cipher");
}
if (data.Length < 96 * 2)
{
throw new Exception("Invalid Cipher");
}
ECDSABase ecdsa = new ECDSABase(new ECCurve("SM2"));
string c1, c2, c3, t;
c1 = data.Substring(0, 128);
c3 = data.Substring(128, 64);
c2 = data.Substring(128 + 64);
t = "";
string x2, y2;
x2 = y2 = "";
bool isZero = true;
BigInteger x = BigInteger.Parse("00" + c1.Substring(0, 64), System.Globalization.NumberStyles.AllowHexSpecifier);
BigInteger y = BigInteger.Parse("00" + c1.Substring(64), System.Globalization.NumberStyles.AllowHexSpecifier);
ECPoint C1 = new ECPoint(x, y);
if (!ECCMath.IsOnCurve(C1))
{
throw new Exception("SM2 Decrypt Failed, C1 Not On Curve");
}
ECPoint S = ECCMath.ScalarMult(ECCurve.h, C1);
if (ECCMath.IsInfinityPoint(S))
{
throw new Exception("S is Infinity Point");
}
BigInteger prikey = BigInteger.Parse("00" + privateKey, System.Globalization.NumberStyles.AllowHexSpecifier);
ECPoint point2 = ECCMath.ScalarMult(prikey, C1);
x2 = Util.ToHexString(point2.X, ECCurve.BitLength);
y2 = Util.ToHexString(point2.Y, ECCurve.BitLength);
t = KDF(x2 + y2, c2.Length * 4);
for (int i = 0; i < t.Length; i++)
{
if (t.Substring(i, 1) == "0")
{
continue;
}
else
{
isZero = false;
break;
}
}
if (isZero)
{
throw new Exception("t = 0");
}
string plaindata = XOR(c2, t);
string u = ALG.GuoMi.SM3(x2 + plaindata + y2);
if (!u.Equals(c3, StringComparison.OrdinalIgnoreCase))
{
throw new Exception("SM2 Decrypt Failed, u != C3");
}
return(plaindata);
}
