C#版本的sha256withRSA 私钥加密 方法

public static string Sign(string contentForSign, string privateKey)
{
	//转换成适用于.Net的秘钥
	var netKey = RSAPrivateKeyJava2DotNet(privateKey);
	var rsa = new RSACryptoServiceProvider();
	rsa.FromXmlString(netKey);
	//创建一个空对象
	var rsaClear = new RSACryptoServiceProvider();
	var paras = rsa.ExportParameters(true);
	rsaClear.ImportParameters(paras);
	//签名返回
	using (var sha256 = new SHA256CryptoServiceProvider())
	{
		var signData = rsa.SignData(Encoding.UTF8.GetBytes(contentForSign), sha256);
		//return BytesToHex(signData);
		return Convert.ToBase64String(signData);
	}
}
public static string RSAPrivateKeyJava2DotNet(string privateKey)
{
	RsaPrivateCrtKeyParameters privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateKey));

	return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent><P>{2}</P><Q>{3}</Q><DP>{4}</DP><DQ>{5}</DQ><InverseQ>{6}</InverseQ><D>{7}</D></RSAKeyValue>",
		Convert.ToBase64String(privateKeyParam.Modulus.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.PublicExponent.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.P.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.Q.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.DP.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.DQ.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.QInv.ToByteArrayUnsigned()),
		Convert.ToBase64String(privateKeyParam.Exponent.ToByteArrayUnsigned()));
}