C#使用Java的秘钥对进行SHA256withRSA签名验签

using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using System;
using System.Security.Cryptography;
using System.Text;
using System.Xml;

/// <summary>
/// RSA私钥，从Java格式转.net格式(不依赖第三方包)
/// </summary>
/// <param name="privateKey">私钥</param>
/// <returns></returns>
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()));
}

/// <summary>
/// 私钥签名
/// </summary>
/// <param name="contentForSign"></param>
/// <param name="privateKey"></param>
/// <returns></returns>
public static string Sign(string contentForSign, string privateKey)
{
var netKey = RSAPrivateKeyJava2DotNet(privateKey); //转换成适用于.net的私钥

var rsa = new RSACryptoServiceProvider();
rsa.FromXmlString(netKey);

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 Convert.ToBase64String(signData);
}
}

/// <summary>
/// RSA公钥，从Java格式转.net格式(不依赖第三方包)
/// </summary>
/// <param name="publikKey"></param>
/// <returns></returns>
public static string RSAPublicKeyJava2DotNet(string publicKey)
{
RsaKeyParameters publicKeyParam = (RsaKeyParameters)PublicKeyFactory.CreateKey(Convert.FromBase64String(publicKey));
return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent></RSAKeyValue>",
Convert.ToBase64String(publicKeyParam.Modulus.ToByteArrayUnsigned()),
Convert.ToBase64String(publicKeyParam.Exponent.ToByteArrayUnsigned()));
}

/// <summary>
/// RSA签名验证
/// </summary>
/// <param name="encryptSource">签名</param>
/// <param name="c">验证的字符串</param>
/// <param name="publicKey">公钥</param>
/// <returns>是否相同，true验证成功，false验证失败。</returns>
public static bool VerifySignature(string encryptSource, string compareString, string publicKey)
{
try
{
using (RSACryptoServiceProvider rsa = FromXmlString(RSAPublicKeyJava2DotNet(publicKey)))
{
//rsa.FromXmlString(RSAPrivateKeyJava2DotNet(publicKey)); .net core3.0直接使用，不需要重写
byte[] signature = Convert.FromBase64String(encryptSource);
SHA256Managed sha256 = new SHA256Managed();
RSAPKCS1SignatureDeformatter df = new RSAPKCS1SignatureDeformatter(rsa);
df.SetHashAlgorithm("SHA256");
byte[] compareByte = sha256.ComputeHash(Encoding.UTF8.GetBytes(compareString));

return df.VerifySignature(compareByte, signature);
}
}
catch (Exception)
{
return false;
}
}

/// <summary>
/// 重写FromXmlString方法
/// </summary>
/// <param name="xmlString"></param>
/// <returns></returns>
public static RSACryptoServiceProvider FromXmlString(string xmlString)
{
var rsa = new RSACryptoServiceProvider();
RSAParameters parameters = new RSAParameters();
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xmlString);
if (xmlDoc.DocumentElement.Name.Equals("RSAKeyValue"))
{
foreach (XmlNode node in xmlDoc.DocumentElement.ChildNodes)
{
switch (node.Name)
{
case "Modulus": parameters.Modulus = Convert.FromBase64String(node.InnerText); break;
case "Exponent": parameters.Exponent = Convert.FromBase64String(node.InnerText); break;
case "P": parameters.P = Convert.FromBase64String(node.InnerText); break;
case "Q": parameters.Q = Convert.FromBase64String(node.InnerText); break;
case "DP": parameters.DP = Convert.FromBase64String(node.InnerText); break;
case "DQ": parameters.DQ = Convert.FromBase64String(node.InnerText); break;
case "InverseQ": parameters.InverseQ = Convert.FromBase64String(node.InnerText); break;
case "D": parameters.D = Convert.FromBase64String(node.InnerText); break;
}
}
}
else
{
throw new Exception("Invalid XML RSA key.");
}

rsa.ImportParameters(parameters);
return rsa;
}

//生成.net   xml   公钥  私钥

public string RsaSign(string data, string privatekey)
{
CspParameters CspParameters = new CspParameters();
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(2048, CspParameters);
byte[] bytes = Encoding.UTF8.GetBytes(data);
privatekey = RSA.ToXmlString(true);
var publickey=RSA.ToXmlString(false);
RSA.FromXmlString(privatekey);
byte[] sign = RSA.SignData(bytes, "SHA256");

return Convert.ToBase64String(sign);
}