.NET Core 使用RSA算法 加密/解密/簽名/驗證簽名

前言

前不久移植了支付寶官方的SDK，以適用ASP.NET Core使用支付寶支付，可是最近有好幾位用戶反應在Linux下使用會出錯，調試發現是RSA加密的錯誤，下面具體講一講。

RSA在.NET Core的改動

之前咱們使用RSA加密主要是使用RSACryptoServiceProvider這個類，在.NET Core中也有這個類，可是這個類並不支持跨平臺，因此若是你是用這個類來進行加/解密在windows上運行是徹底沒有錯誤的，可是隻要你一放到Linux下就會出現異常。

查閱資料得知，要解決這個問題，須要改用 System.Security.Cryptography.RSA.Create() 工廠方法，使用它以後，在 Windows 上建立的是 System.Security.Cryptography.RSACng 的實例，在 Mac 與 Linux 上建立的是 System.Security.Cryptography.RSAOpenSsl 的實例，它們都繼承自 System.Security.Cryptography.RSA 抽象類。

RSACng：

相關資料：https://docs.microsoft.com/zh-cn/dotnet/api/system.security.cryptography.rsacng?view=netcore-2.0

RSAOpenSsl ：

相關資料：https://docs.microsoft.com/zh-cn/dotnet/api/system.security.cryptography.rsaopenssl?view=netcore-2.0

在Windows上的調試截圖：

在Mac上使用Visual studio For Mac 調試截圖：

RSA公鑰/私鑰說明

這裏的RSA加密/解密主要是針對於由OpenSSL生成的公鑰/私鑰字符串。ssh-keygen -t rsa 命令生成的公鑰私鑰是不行的。

公鑰示例：

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

私鑰示例：

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

公鑰/私鑰生成

Windows&MAC_OSX能夠使用有支付寶開發的RSA密鑰生成工具：

使用此工具生成的時候必定要選擇，PKCS1

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

此外還能夠使用OpenSSL工具命令來生成：https://doc.open.alipay.com/docs/doc.htm?articleId=106130&docType=1

.NET Core 中的使用

這裏要講一下RSA2算法。

什麼是RSA2 ？RSA2 是在原來SHA1WithRSA簽名算法的基礎上，新增了支持SHA256WithRSA的簽名算法。該算法比SHA1WithRSA有更強的安全能力。

算法名稱	標準簽名算法名稱	備註
RSA2	SHA256WithRSA	（強烈推薦使用），強制要求RSA密鑰的長度至少爲2048
RSA	SHA1WithRSA	對RSA密鑰的長度不限制，推薦使用2048位以上

簽名的做用:保證數據完整性,機密性和發送方角色的不可抵賴性

這裏來一發乾貨，我已經封裝好的RSA/RSA2算法，支持加密/解密/簽名/驗證簽名。

/// <summary>
/// RSA加解密 使用OpenSSL的公鑰加密/私鑰解密
/// 做者：李志強
/// 建立時間：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>
    /// 實例化RSAHelper
    /// </summary>
    /// <param name="rsaType">加密算法類型 RSA SHA1;RSA2 SHA256 密鑰長度至少爲2048</param>
    /// <param name="encoding">編碼類型</param>
    /// <param name="privateKey">私鑰</param>
    /// <param name="publicKey">公鑰</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 使用私鑰簽名

    /// <summary>
    /// 使用私鑰簽名
    /// </summary>
    /// <param name="data">原始數據</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 使用公鑰驗證簽名

    /// <summary>
    /// 使用公鑰驗證簽名
    /// </summary>
    /// <param name="data">原始數據</param>
    /// <param name="sign">簽名</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 使用私鑰建立RSA實例

    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 使用公鑰建立RSA實例

    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 導入密鑰算法

    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算法類型
/// </summary>
public enum RSAType
{
    /// <summary>
    /// SHA1
    /// </summary>
    RSA = 0,
    /// <summary>
    /// RSA2 密鑰長度至少爲2048
    /// SHA256
    /// </summary>
    RSA2
}

使用：

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

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

    string str = "博客園 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);

    //私鑰簽名
    string signStr = rsa.Sign(str);

    Console.WriteLine("字符串簽名：" + signStr);

    //公鑰驗證簽名
    bool signVerify = rsa.Verify(str,signStr);

    Console.WriteLine("驗證簽名：" + signVerify);

    Console.ReadKey();
}

運行：

參考

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

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