C# 实现RSA加解密

偏执的太偏执、 2021-12-15 08:43 444阅读 0赞

**对称加密(DES、3DES)、非对称加密(RSA、SHA1withRSA)**

**参考: **[https://blog.csdn.net/sinat\_16998945/article/details/94639023][https_blog.csdn.net_sinat_16998945_article_details_94639023]

### 一、支付宝工具生成公钥私钥 ###

下载地址链接: https://pan.baidu.com/s/15L1GM8mK43tzV9XyyNEV8Q

提取码: vux3

使用方法可参考阿里文档：[https://docs.open.alipay.com/291/105971/][https_docs.open.alipay.com_291_105971]

### 二、加密 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70][]

说明：1.使用公钥加密，  2.加密后每次结果是可变的

### 三、解密 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70 1][]

说明：1.使用私钥解密

### 四、实现代码 ###

利用工具可生成公私秘钥，注意(java版本与非java版本)

1.公钥  "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCO772dmiRP4HaddeZTUieS4SWrNnbRPIgxoF5wLZNK1nel3hf7uffWkZ5lzjSuLig5sgPzU/oQgophIG9+NwoHeyXPgnhNV8zPluueHFrQzrSnq9jhUS1yxTezmYr+oxAQIyGQUZO21Sg1+2lqDyatPpRfN4JSKusAw9yOcbkHKQIDAQAB"

2.私钥  "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"

3.加密调用：RSA.RasEncrypt("公钥 ", "待加密字符串", "UTF-8");

4.解密调用：RSA.RsaDecrypt("公钥 ", "RSA加密后字符串", "UTF-8");

using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Security.Cryptography;
    using System.Text;
    using System.Threading.Tasks;
    
    namespace Common
    {
        public class RSA
        {
            /// <summary>
            /// RSA公钥加密
            /// </summary>
            /// <param name="publickey">公钥</param>
            /// <param name="content">待加密字符串</param>
            /// <param name="input_charset">编码格式，UTF-8</param>
            /// <returns></returns>
            public static string RasEncrypt(string publickey, string content, string input_charset)
            {
                RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
                byte[] cipherbytes;
                rsa.ImportParameters(ConvertFromPublicKey(publickey));
                cipherbytes = rsa.Encrypt(Encoding.GetEncoding(input_charset).GetBytes(content), false);
                return Convert.ToBase64String(cipherbytes);
            }
    
            /// <summary>
            /// RSA私钥解密
            /// </summary>
            /// <param name="resData">RSA加密后字符串</param>
            /// <param name="privateKey">私钥</param>
            /// <param name="input_charset">编码格式，UTF-8</param>
            /// <returns>明文</returns>
            public static string RsaDecrypt(string resData, string privateKey, string input_charset)
            {
                byte[] DataToDecrypt = Convert.FromBase64String(resData);
                string result = "";
                for (int j = 0; j < DataToDecrypt.Length / 128; j++)
                {
                    byte[] buf = new byte[128];
                    for (int i = 0; i < 128; i++)
                    {
    
                        buf[i] = DataToDecrypt[i + 128 * j];
                    }
                    result += decrypt(buf, privateKey, input_charset);
                }
                return result;
            }
    
            #region 内部方法
    
            private static string decrypt(byte[] data, string privateKey, string input_charset)
            {
                string result = "";
                RSACryptoServiceProvider rsa = DecodePemPrivateKey(privateKey);
                using (var sh = SHA1.Create())
                {
                    byte[] source = rsa.Decrypt(data, false);
                    char[] asciiChars = new char[Encoding.GetEncoding(input_charset).GetCharCount(source, 0, source.Length)];
                    Encoding.GetEncoding(input_charset).GetChars(source, 0, source.Length, asciiChars, 0);
                    result = new string(asciiChars);
                    return result;
                }
    
            }
    
            private static RSACryptoServiceProvider DecodePemPrivateKey(String pemstr)
            {
                RSACryptoServiceProvider rsa = DecodeRSAPrivateKey(Convert.FromBase64String(pemstr));
                return rsa;
            }
    
            private static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey)
            {
                byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;
    
                // --------- Set up stream to decode the asn.1 encoded RSA private key ------
                MemoryStream mem = new MemoryStream(privkey);
                BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
                byte bt = 0;
                ushort twobytes = 0;
                int elems = 0;
                try
                {
                    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();
                    if (twobytes != 0x0102) //version number
                        return null;
                    bt = binr.ReadByte();
                    if (bt != 0x00)
                        return null;
    
    
                    //------ all private key components are Integer sequences ----
                    elems = GetIntegerSize(binr);
                    MODULUS = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    E = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    D = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    P = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    Q = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    DP = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    DQ = binr.ReadBytes(elems);
    
                    elems = GetIntegerSize(binr);
                    IQ = binr.ReadBytes(elems);
    
    
                    // ------- create RSACryptoServiceProvider instance and initialize with public key -----
                    CspParameters CspParameters = new CspParameters();
                    CspParameters.Flags = CspProviderFlags.UseMachineKeyStore;
                    RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(1024, CspParameters);
                    RSAParameters RSAparams = new RSAParameters();
                    RSAparams.Modulus = MODULUS;
                    RSAparams.Exponent = E;
                    RSAparams.D = D;
                    RSAparams.P = P;
                    RSAparams.Q = Q;
                    RSAparams.DP = DP;
                    RSAparams.DQ = DQ;
                    RSAparams.InverseQ = IQ;
                    RSA.ImportParameters(RSAparams);
                    return RSA;
                }
                catch
                {
                    return null;
                }
                finally
                {
                    binr.Dispose();
                }
            }
    
            private static int GetIntegerSize(BinaryReader binr)
            {
                byte bt = 0;
                byte lowbyte = 0x00;
                byte highbyte = 0x00;
                int count = 0;
                bt = binr.ReadByte();
                if (bt != 0x02) //expect integer
                    return 0;
                bt = binr.ReadByte();
    
                if (bt == 0x81)
                    count = binr.ReadByte(); // data size in next byte
                else
                    if (bt == 0x82)
                {
                    highbyte = binr.ReadByte(); // data size in next 2 bytes
                    lowbyte = binr.ReadByte();
                    byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
                    count = BitConverter.ToInt32(modint, 0);
                }
                else
                {
                    count = bt; // we already have the data size
                }
    
                while (binr.ReadByte() == 0x00)
                { //remove high order zeros in data
                    count -= 1;
                }
                binr.BaseStream.Seek(-1, SeekOrigin.Current); //last ReadByte wasn't a removed zero, so back up a byte
                return count;
            }
    
            #endregion
    
            #region 生成的Pem
            private static RSAParameters ConvertFromPublicKey(string pemFileConent)
            {
    
                if (string.IsNullOrEmpty(pemFileConent))
                {
                    throw new ArgumentNullException("pemFileConent", "This arg cann't be empty.");
                }
                pemFileConent = pemFileConent.Replace("-----BEGIN PUBLIC KEY-----", "").Replace("-----END PUBLIC KEY-----", "").Replace("\n", "").Replace("\r", "");
                byte[] keyData = Convert.FromBase64String(pemFileConent);
                bool keySize1024 = (keyData.Length == 162);
                bool keySize2048 = (keyData.Length == 294);
                if (!(keySize1024 || keySize2048))
                {
                    throw new ArgumentException("pem file content is incorrect, Only support the key size is 1024 or 2048");
                }
                byte[] pemModulus = (keySize1024 ? new byte[128] : new byte[256]);
                byte[] pemPublicExponent = new byte[3];
                Array.Copy(keyData, (keySize1024 ? 29 : 33), pemModulus, 0, (keySize1024 ? 128 : 256));
                Array.Copy(keyData, (keySize1024 ? 159 : 291), pemPublicExponent, 0, 3);
                RSAParameters para = new RSAParameters();
                para.Modulus = pemModulus;
                para.Exponent = pemPublicExponent;
                return para;
            }
    
            #endregion
    
        }
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70 2][]

[https_blog.csdn.net_sinat_16998945_article_details_94639023]: https://blog.csdn.net/sinat_16998945/article/details/94639023
[https_docs.open.alipay.com_291_105971]: https://docs.open.alipay.com/291/105971/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70]: /images/20211214/c2af1ce5b4ef45d7b58ca14f4b816759.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70 1]: /images/20211214/a21a0fa3ad4f4adda79898a3877071f1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzE2OTk4OTQ1_size_16_color_FFFFFF_t_70 2]: /images/20211214/68884cef1f0b48ce93ad7ecb9369ee0b.png