.NET Core 使用RSA算法 加密/解密/签名/验证签名

前言

前不久移植了支付宝官方的SDK，以适用ASP.NET Core使用支付宝支付，但是最近有好几位用户反应在Linux下使用会出错，调试发现是RSA加密的错误，下面具体讲一讲。

RSA在.NET Core的改动

以前我们使用RSA加密主要是使用RSACryptoServiceProvider这个类，在.NET Core中也有这个类，但是这个类并不支持跨平台，所以如果你是用这个类来进行加/解密在windows上运行是完全没有错误的，但是只要你一放到Linux下就会出现异常。

查阅资料得知，要解决这个问题，需要改用 System.Security.Cryptography.RSA.Create() 工厂方法，使用它之后，在 Windows 上创建的是 System.Security.Cryptography.RSACng 的实例，在 Mac 与 Linux 上创建的是 System.Security.Cryptography.RSAOpenSsl 的实例，它们都继承自 System.Security.Cryptography.RSA 抽象类。

RSACng：

相关资料：https://docs.microsoft.com/zh-cn/dotnet/api/system.security.cryptography.rsacng?view=netcore-2.0

RSAOpenSsl ：

相关资料：https://docs.microsoft.com/zh-cn/dotnet/api/system.security.cryptography.rsaopenssl?view=netcore-2.0

在Windows上的调试截图：

在Mac上使用Visual studio For Mac 调试截图：

RSA公钥/私钥说明

这里的RSA加密/解密主要是针对于由OpenSSL生成的公钥/私钥字符串。ssh-keygen -t rsa 命令生成的公钥私钥是不行的。

公钥示例：

-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC7PyjMEuniN6BPn8oqzIZ6AO1N
jSTO9R3adCCIwKfKIEoWXXM+tHDpktdPKSaAsWJPTNAGvEvtxOfzXib/EMXKqD0e
Uy5MatfpRjRdf1hJVimmfrb09Qx2j7CsKLy7nD23m4xubdYBwvkjMwt/L3JxB5D6
qryW1wei/j1c+/OCxQIDAQAB
-----END PUBLIC KEY-----

私钥示例：

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

公钥/私钥生成

Windows&MAC_OSX可以使用有支付宝开发的RSA密钥生成工具：

使用此工具生成的时候一定要选择，PKCS1

下载地址：https://doc.open.alipay.com/docs/doc.htm?treeId=291&articleId=105971&docType=1

此外还可以使用OpenSSL工具命令来生成：https://doc.open.alipay.com/docs/doc.htm?articleId=106130&docType=1

.NET Core 中的使用

这里要讲一下RSA2算法。

什么是RSA2 ？RSA2 是在原来SHA1WithRSA签名算法的基础上，新增了支持SHA256WithRSA的签名算法。该算法比SHA1WithRSA有更强的安全能力。

算法名称	标准签名算法名称	备注
RSA2	SHA256WithRSA	（强烈推荐使用），强制要求RSA密钥的长度至少为2048
RSA	SHA1WithRSA	对RSA密钥的长度不限制，推荐使用2048位以上

签名的作用:保证数据完整性,机密性和发送方角色的不可抵赖性

这里来一发干货，我已经封装好的RSA/RSA2算法，支持加密/解密/签名/验证签名。

/// <summary>
/// RSA加解密 使用OpenSSL的公钥加密/私钥解密
/// 作者：李志强
/// 创建时间：2017年10月30日15:50:14
/// QQ:501232752
/// </summary>
public class RSAHelper
{
	private readonly RSA _privateKeyRsaProvider;
	private readonly RSA _publicKeyRsaProvider;
	private readonly HashAlgorithmName _hashAlgorithmName;
	private readonly Encoding _encoding;

	/// <summary>
	/// 实例化RSAHelper
	/// </summary>
	/// <param name="rsaType">加密算法类型 RSA SHA1;RSA2 SHA256 密钥长度至少为2048</param>
	/// <param name="encoding">编码类型</param>
	/// <param name="privateKey">私钥</param>
	/// <param name="publicKey">公钥</param>
	public RSAHelper(RSAType rsaType, Encoding encoding, string privateKey, string publicKey = null)
	{
		_encoding = encoding;
		if (!string.IsNullOrEmpty(privateKey))
		{
			_privateKeyRsaProvider = CreateRsaProviderFromPrivateKey(privateKey);
		}

		if (!string.IsNullOrEmpty(publicKey))
		{
			_publicKeyRsaProvider = CreateRsaProviderFromPublicKey(publicKey);
		}

		_hashAlgorithmName = rsaType == RSAType.RSA ? HashAlgorithmName.SHA1 : HashAlgorithmName.SHA256;
	}

	#region 使用私钥签名

	/// <summary>
	/// 使用私钥签名
	/// </summary>
	/// <param name="data">原始数据</param>
	/// <returns></returns>
	public string Sign(string data)
	{
		byte[] dataBytes = _encoding.GetBytes(data);

		var signatureBytes = _privateKeyRsaProvider.SignData(dataBytes, _hashAlgorithmName, RSASignaturePadding.Pkcs1);

		return Convert.ToBase64String(signatureBytes);
	}

	#endregion

	#region 使用公钥验证签名

	/// <summary>
	/// 使用公钥验证签名
	/// </summary>
	/// <param name="data">原始数据</param>
	/// <param name="sign">签名</param>
	/// <returns></returns>
	public bool Verify(string data,string sign)
	{
		byte[] dataBytes = _encoding.GetBytes(data);
		byte[] signBytes = Convert.FromBase64String(sign);

		var verify = _publicKeyRsaProvider.VerifyData(dataBytes, signBytes, _hashAlgorithmName, RSASignaturePadding.Pkcs1);

		return verify;
	}

	#endregion

	#region 解密

	public string Decrypt(string cipherText)
	{
		if (_privateKeyRsaProvider == null)
		{
			throw new Exception("_privateKeyRsaProvider is null");
		}
		return Encoding.UTF8.GetString(_privateKeyRsaProvider.Decrypt(Convert.FromBase64String(cipherText), RSAEncryptionPadding.Pkcs1));
	}

	#endregion

	#region 加密

	public string Encrypt(string text)
	{
		if (_publicKeyRsaProvider == null)
		{
			throw new Exception("_publicKeyRsaProvider is null");
		}
		return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(Encoding.UTF8.GetBytes(text), RSAEncryptionPadding.Pkcs1));
	}

	#endregion

	#region 使用私钥创建RSA实例

	public RSA CreateRsaProviderFromPrivateKey(string privateKey)
	{
		var privateKeyBits = Convert.FromBase64String(privateKey);

		var rsa = RSA.Create();
		var rsaParameters = new RSAParameters();

		using (BinaryReader binr = new BinaryReader(new MemoryStream(privateKeyBits)))
		{
			byte bt = 0;
			ushort twobytes = 0;
			twobytes = binr.ReadUInt16();
			if (twobytes == 0x8130)
				binr.ReadByte();
			else if (twobytes == 0x8230)
				binr.ReadInt16();
			else
				throw new Exception("Unexpected value read binr.ReadUInt16()");

			twobytes = binr.ReadUInt16();
			if (twobytes != 0x0102)
				throw new Exception("Unexpected version");

			bt = binr.ReadByte();
			if (bt != 0x00)
				throw new Exception("Unexpected value read binr.ReadByte()");

			rsaParameters.Modulus = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.Exponent = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.D = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.P = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.Q = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.DP = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.DQ = binr.ReadBytes(GetIntegerSize(binr));
			rsaParameters.InverseQ = binr.ReadBytes(GetIntegerSize(binr));
		}

		rsa.ImportParameters(rsaParameters);
		return rsa;
	}

	#endregion

	#region 使用公钥创建RSA实例

	public RSA CreateRsaProviderFromPublicKey(string publicKeyString)
	{
		// encoded OID sequence for  PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
		byte[] seqOid = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
		byte[] seq = new byte[15];

		var x509Key = Convert.FromBase64String(publicKeyString);

		// ---------  Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob  ------
		using (MemoryStream mem = new MemoryStream(x509Key))
		{
			using (BinaryReader binr = new BinaryReader(mem))  //wrap Memory Stream with BinaryReader for easy reading
			{
				byte bt = 0;
				ushort twobytes = 0;

				twobytes = binr.ReadUInt16();
				if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
					binr.ReadByte();    //advance 1 byte
				else if (twobytes == 0x8230)
					binr.ReadInt16();   //advance 2 bytes
				else
					return null;

				seq = binr.ReadBytes(15);       //read the Sequence OID
				if (!CompareBytearrays(seq, seqOid))    //make sure Sequence for OID is correct
					return null;

				twobytes = binr.ReadUInt16();
				if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
					binr.ReadByte();    //advance 1 byte
				else if (twobytes == 0x8203)
					binr.ReadInt16();   //advance 2 bytes
				else
					return null;

				bt = binr.ReadByte();
				if (bt != 0x00)     //expect null byte next
					return null;

				twobytes = binr.ReadUInt16();
				if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
					binr.ReadByte();    //advance 1 byte
				else if (twobytes == 0x8230)
					binr.ReadInt16();   //advance 2 bytes
				else
					return null;

				twobytes = binr.ReadUInt16();
				byte lowbyte = 0x00;
				byte highbyte = 0x00;

				if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
					lowbyte = binr.ReadByte();  // read next bytes which is bytes in modulus
				else if (twobytes == 0x8202)
				{
					highbyte = binr.ReadByte(); //advance 2 bytes
					lowbyte = binr.ReadByte();
				}
				else
					return null;
				byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };   //reverse byte order since asn.1 key uses big endian order
				int modsize = BitConverter.ToInt32(modint, 0);

				int firstbyte = binr.PeekChar();
				if (firstbyte == 0x00)
				{   //if first byte (highest order) of modulus is zero, don't include it
					binr.ReadByte();    //skip this null byte
					modsize -= 1;   //reduce modulus buffer size by 1
				}

				byte[] modulus = binr.ReadBytes(modsize);   //read the modulus bytes

				if (binr.ReadByte() != 0x02)            //expect an Integer for the exponent data
					return null;
				int expbytes = (int)binr.ReadByte();        // should only need one byte for actual exponent data (for all useful values)
				byte[] exponent = binr.ReadBytes(expbytes);

				// ------- create RSACryptoServiceProvider instance and initialize with public key -----
				var rsa = RSA.Create();
				RSAParameters rsaKeyInfo = new RSAParameters
				{
					Modulus = modulus,
					Exponent = exponent
				};
				rsa.ImportParameters(rsaKeyInfo);

				return rsa;
			}

		}
	}

	#endregion

	#region 导入密钥算法

	private int GetIntegerSize(BinaryReader binr)
	{
		byte bt = 0;
		int count = 0;
		bt = binr.ReadByte();
		if (bt != 0x02)
			return 0;
		bt = binr.ReadByte();

		if (bt == 0x81)
			count = binr.ReadByte();
		else
		if (bt == 0x82)
		{
			var highbyte = binr.ReadByte();
			var lowbyte = binr.ReadByte();
			byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
			count = BitConverter.ToInt32(modint, 0);
		}
		else
		{
			count = bt;
		}

		while (binr.ReadByte() == 0x00)
		{
			count -= 1;
		}
		binr.BaseStream.Seek(-1, SeekOrigin.Current);
		return count;
	}

	private bool CompareBytearrays(byte[] a, byte[] b)
	{
		if (a.Length != b.Length)
			return false;
		int i = 0;
		foreach (byte c in a)
		{
			if (c != b[i])
				return false;
			i++;
		}
		return true;
	}

	#endregion

}

/// <summary>
/// RSA算法类型
/// </summary>
public enum RSAType
{
	/// <summary>
	/// SHA1
	/// </summary>
	RSA = 0,
	/// <summary>
	/// RSA2 密钥长度至少为2048
	/// SHA256
	/// </summary>
	RSA2
}

使用：

static void Main(string[] args)
{
	//2048 公钥
	string publicKey =
		"MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoQh0wEqx/R2H1v00IU12Oc30fosRC/frhH89L6G+fzeaqI19MYQhEPMU13wpeqRONCUta+2iC1sgCNQ9qGGf19yGdZUfueaB1Nu9rdueQKXgVurGHJ+5N71UFm+OP1XcnFUCK4wT5d7ZIifXxuqLehP9Ts6sNjhVfa+yU+VjF5HoIe69OJEPo7OxRZcRTe17khc93Ic+PfyqswQJJlY/bgpcLJQnM+QuHmxNtF7/FpAx9YEQsShsGpVo7JaKgLo+s6AFoJ4QldQKir2vbN9vcKRbG3piElPilWDpjXQkOJZhUloh/jd7QrKFimZFldJ1r6Q59QYUyGKZARUe0KZpMQIDAQAB";
	//2048 私钥
	string privateKey =
		"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";

	var rsa = new RSAHelper(RSAType.RSA2,Encoding.UTF8, privateKey, publicKey);

	string str = "博客园 http://www.cnblogs.com/";

	Console.WriteLine("原始字符串："+str);

	//加密
	string enStr = rsa.Encrypt(str);

	Console.WriteLine("加密字符串："+enStr);

	//解密
	string deStr = rsa.Decrypt(enStr);

	Console.WriteLine("解密字符串："+deStr);

	//私钥签名
	string signStr = rsa.Sign(str);

	Console.WriteLine("字符串签名：" + signStr);

	//公钥验证签名
	bool signVerify = rsa.Verify(str,signStr);

	Console.WriteLine("验证签名：" + signVerify);

	Console.ReadKey();
}

运行：

参考

• http://www.cnblogs.com/dudu/p/dotnet-core-rsa-openssl.html

本文Demo：https://github.com/stulzq/DotnetCore.RSA