C#.NET Framework 使用BC库（BouncyCastle） RSA 公钥加密私钥解密 ver:20230706

技术分享 3年前 (2023-07-06) 0 999+

环境说明：

.NET Framework 4.6 的控制台程序。

2020年以后，有部分PKCS8私钥（openssl生成）无法用RsaUtil.LoadPrivateKey(strPriPkcs8, "PKCS8")来解析（https://www.cnblogs.com/runliuv/p/17474269.html）

可以尝试用BC库来处理。

另外，在.NET中：私钥加密，公钥解密。也只能用BC库实现。

加密解析：

//假设私钥长度为1024， 1024/8-11=117。
//如果明文的长度小于117，直接全加密，然后转base64。(data.Length <= maxBlockSize)
//如果明文长度大于117，则每117分一段加密，写入到另一个Stream中，最后转base64。

如果要和其它语言互通，这个分段长度需要和其它语言约定好，不一是私钥长度/8-11。

解密解析：

//假设私钥长度为1024， 1024/8 =128。
//如果明文的长度小于 128，直接全解密。(data.Length <= maxBlockSize)
//如果明文长度大于 128，则每 128 分一段解密，写入到另一个Stream中，最后 GetString。

用“支付宝开放平台开发助手”生成一组公私钥：

PKCS8私钥：

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

与之匹配的 PKCS1 私钥，用助手转换的：

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

与之匹配的公钥：

MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDM9As4OkFLUyEmtqVJJaHkAf0xKR3aq38q6FqSi1vQfy1hUjhh/Z8k5NaT2WnmnchGUOoGsvwtKVAHrS62qvWzAPy7sauvG/O7hu1l+3SsrRDtv/O6hqRjEbPex/hpZM1opdkDtiiuHB5wHFYnD7JouWme9lNAViRcj4bXfqnZqwIDAQAB

BCSignUtil 辅助类，nuget 中引用 Portable.BouncyCastle。

using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Encodings; using Org.BouncyCastle.Crypto.Engines; using Org.BouncyCastle.Security; using System; using System.IO; using System.Text;  namespace CommonUtils {     public static class BCSignUtil     {         /// <summary>         /// 签名         /// </summary>         /// <param name="orgData">原数据字符串</param>         /// <param name="privateKeyPKCS8">必须是PKCS8的</param>         /// <param name="algorithm">算法</param>         /// <returns></returns>         public static string SignData(string orgData, string privateKeyPKCS8, string algorithm)         {             if (string.IsNullOrEmpty(orgData))                 throw new Exception("字符串不能为空!");              if (string.IsNullOrEmpty(privateKeyPKCS8))                 throw new Exception("privateKeyPKCS8不能为空!");              if (string.IsNullOrEmpty(privateKeyPKCS8))                 throw new Exception("algorithm 不能为空!");              AsymmetricKeyParameter priKey = GetPrivateKeyParameter(privateKeyPKCS8);              byte[] byteData = Encoding.UTF8.GetBytes(orgData);              ISigner normalSig = SignerUtilities.GetSigner(algorithm);             normalSig.Init(true, priKey);             normalSig.BlockUpdate(byteData, 0, byteData.Length);//注意：是byte数组和数组长度，别写成string的长度了             byte[] normalResult = normalSig.GenerateSignature(); //签名结果             string sign = Convert.ToBase64String(normalResult);              return sign;         }          private static AsymmetricKeyParameter GetPrivateKeyParameter(string privateKeyPem)         {             //获取私钥纯字符串             privateKeyPem = privateKeyPem.Replace("-----BEGIN RSA PRIVATE KEY-----", "").Replace("-----END RSA PRIVATE KEY-----", "").Replace("r", "").Replace("n", "").Trim();             privateKeyPem = privateKeyPem.Replace("-----BEGIN PRIVATE KEY-----", "").Replace("-----END PRIVATE KEY-----", "").Replace("r", "").Replace("n", "").Trim();              byte[] privateInfoByte = Convert.FromBase64String(privateKeyPem);              AsymmetricKeyParameter priKey = PrivateKeyFactory.CreateKey(privateInfoByte);             return priKey;         }          /// <summary>         /// 验证签名         /// </summary>         /// <param name="orgData">原数据字符串</param>         /// <param name="publicKeyPem">公钥</param>         /// <param name="responseSign">对方的签名串</param>         /// <param name="algorithm">算法</param>         /// <returns></returns>         public static bool VerifySignature(string orgData, string publicKeyPem, string responseSign, string algorithm)         {              AsymmetricKeyParameter pubKey = GetPublicKeyParameter(publicKeyPem);               byte[] signBytes = Convert.FromBase64String(responseSign);             byte[] plainBytes = Encoding.UTF8.GetBytes(orgData);              ISigner verifier = SignerUtilities.GetSigner(algorithm);             verifier.Init(false, pubKey);             verifier.BlockUpdate(plainBytes, 0, plainBytes.Length);//注意：是byte数组和数组长度，别写成string的长度了              bool isOK = verifier.VerifySignature(signBytes); //验签结果             return isOK;         }          private static AsymmetricKeyParameter GetPublicKeyParameter(string publicKeyPem)         {             //获取公钥纯字符串             publicKeyPem = publicKeyPem.Replace("-----BEGIN PUBLIC KEY-----", "").Replace("-----END PUBLIC KEY-----", "").Replace("r", "").Replace("n", "").Trim();              byte[] publicInfoByte = Convert.FromBase64String(publicKeyPem);              AsymmetricKeyParameter pubKey = PublicKeyFactory.CreateKey(publicInfoByte);             return pubKey;         }          /// <summary>         /// RSA加密         /// </summary>         /// <param name="orgData">数据</param>         /// <param name="key">私钥、公钥</param>         /// <param name="isPublicKey">是否为公钥</param>         /// <param name="privateKeySize">私钥长度，一般是1024或2048</param>         /// <returns></returns>         public static string EncryptByKey(string orgData, string key, bool isPublicKey, int privateKeySize)         {             //非对称加密算法，加解密用               IAsymmetricBlockCipher engine = new Pkcs1Encoding(new RsaEngine());             //加密                //1024长度是117，双方协商好             int maxBlockSize = privateKeySize / 8 - 11; //加密块最大长度限制              engine.Init(true, isPublicKey ? GetPublicKeyParameter(key) : GetPrivateKeyParameter(key));             byte[] byteData = System.Text.Encoding.UTF8.GetBytes(orgData);              int inputLen = byteData.Length;             MemoryStream ms = new MemoryStream();             int offSet = 0;             byte[] cache;             int i = 0;             // 对数据分段加密             while (inputLen - offSet > 0)             {                 if (inputLen - offSet > maxBlockSize)                 {                     cache = engine.ProcessBlock(byteData, offSet, maxBlockSize);                 }                 else                 {                     cache = engine.ProcessBlock(byteData, offSet, inputLen - offSet);                 }                 ms.Write(cache, 0, cache.Length);                 i++;                 offSet = i * maxBlockSize;             }             byte[] encryptedData = ms.ToArray();              //var ResultData = engine.ProcessBlock(byteData, 0, byteData.Length);             return Convert.ToBase64String(encryptedData);             //Console.WriteLine("密文（base64编码）:" + Convert.ToBase64String(testData) + Environment.NewLine);          }         /// <summary>         /// RSA解密         /// </summary>         /// <param name="orgData">数据</param>         /// <param name="key">私钥、公钥</param>         /// <param name="isPublicKey">是否为公钥</param>         /// <param name="privateKeySize">私钥长度，一般是1024或2048</param>         /// <returns></returns>         public static string DecryptByKey(string orgData, string key, bool isPublicKey, int privateKeySize)         {             orgData = orgData.Replace("r", "").Replace("n", "").Replace(" ", "");             //非对称加密算法，加解密用               IAsymmetricBlockCipher engine = new Pkcs1Encoding(new RsaEngine());               //解密                 //1024长度是128，双方协商好             int maxBlockSize = privateKeySize / 8; //解密块最大长度限制              engine.Init(false, isPublicKey ? GetPublicKeyParameter(key) : GetPrivateKeyParameter(key));             byte[] byteData = Convert.FromBase64String(orgData);              int inputLen = byteData.Length;             MemoryStream ms = new MemoryStream();             int offSet = 0;             byte[] cache;             int i = 0;             // 对数据分段加密             while (inputLen - offSet > 0)             {                 if (inputLen - offSet > maxBlockSize)                 {                     cache = engine.ProcessBlock(byteData, offSet, maxBlockSize);                 }                 else                 {                     cache = engine.ProcessBlock(byteData, offSet, inputLen - offSet);                 }                 ms.Write(cache, 0, cache.Length);                 i++;                 offSet = i * maxBlockSize;             }             byte[] encryptedData = ms.ToArray();              //var ResultData = engine.ProcessBlock(byteData, 0, byteData.Length);             return Encoding.UTF8.GetString(ms.ToArray());             //Console.WriteLine("密文（base64编码）:" + Convert.ToBase64String(testData) + Environment.NewLine);          }      } }

使用代码：

using CommonUtils; using System;  namespace ConsoleNetFxRsa加密签名使用BC库 {     class Program     {         static void Main(string[] args)         {             try             {                 //PKCS8格式私钥                 string strPriPkcs8 = "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";                 //PKCS1格式私钥                 string strPriPkcs1 = "MIICXwIBAAKBgQDM9As4OkFLUyEmtqVJJaHkAf0xKR3aq38q6FqSi1vQfy1hUjhh/Z8k5NaT2WnmnchGUOoGsvwtKVAHrS62qvWzAPy7sauvG/O7hu1l+3SsrRDtv/O6hqRjEbPex/hpZM1opdkDtiiuHB5wHFYnD7JouWme9lNAViRcj4bXfqnZqwIDAQABAoGBAL1uu4gG4B7dAQElQ/Qt4ko6RGlR1ZQteuaPyFc2k3BMfAc91XtMzfFtyZ7yDt3m7BuB4iy69jZPvva5bTnNHjXhjL+xdXvzhaLdcDdDjerNYOG2Idc+VM/BXGIjFnKhxyAq8fqEhXivcfiNmYHu3p0F3LFZ6hIZu+2ROWHM0q8hAkEA/ZwefHuXn2HIRfnGG5lEYqF9fHFDLoUGwfQKtjeeXHevPS4N+Smak/CUE6f/LUEnQiRvHdp1PFSrKVCkxALmgwJBAM7iiCKHPT1Sb8vdC4SDwPXNUvATwiOxDAmk2aieaN1Wkdnar1GQxl+5C95GJEPp+5qtyiBAr5BBcwPhTj/el7kCQQCUEyh1tE/2HkiqGslB6f5UvEehdhwsuD0W15+9fsH26WanCRHdjh4UDN7YjzldufHrG4zJWHklDaaWS+C4FZ1zAkEAuy77PUJfhjwwKqO06BDNZZiAkfdOkDyAR7l/tbCd8KWDETlrpsD2u2UR9+o+pbPukeTsHIJqVnrhNYGE6wTbAQJBAJ9qRLQJY19X6EH3+gi6M2IPyeifUZlRXCeqs9C199OdqjRQUGMPAjBwe1ZFTc7AyAwvC1+bj9qc063Ty3sPqTw=";                 //公钥                 string strPub = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDM9As4OkFLUyEmtqVJJaHkAf0xKR3aq38q6FqSi1vQfy1hUjhh/Z8k5NaT2WnmnchGUOoGsvwtKVAHrS62qvWzAPy7sauvG/O7hu1l+3SsrRDtv/O6hqRjEbPex/hpZM1opdkDtiiuHB5wHFYnD7JouWme9lNAViRcj4bXfqnZqwIDAQAB";                  string strDJM = "泰酷拉！123ABC";//待签名字符串                 strDJM = "泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC泰酷拉！123ABC";//待加密字符串，超过117字符的测试                  Console.WriteLine("待签名字符串：" + strDJM);                                  #region 一、私钥签名                 //string algorithm = "SHA1withRSA";                 string algorithm = "SHA256withRSA";                 string strSigned = BCSignUtil.SignData(strDJM, strPriPkcs8, algorithm); //PKCS8                 Console.WriteLine("签名值：" + strSigned);                 #endregion                  #region 二、公钥验签（验证签名）                 //二、公钥验签（验证签名）                 //验证签名                 bool bCheck = BCSignUtil.VerifySignature(strDJM, strPub, strSigned, algorithm);//验证签名双方要保持一致                 Console.WriteLine("验证签名：" + bCheck.ToString());                 #endregion 
　　　　　　　　　　//私钥长度，常用 1024 或 2048                 int privateKeySize = 1024;                  //公钥加密                string strJiamihou=  BCSignUtil.EncryptByKey(strDJM, strPub,true, privateKeySize);                 Console.WriteLine("加密后：" + strJiamihou);                  //私钥解密                 string strJiemihou = BCSignUtil.DecryptByKey(strJiamihou, strPriPkcs8, false, privateKeySize);                 Console.WriteLine("解密后：" + strJiemihou);                  //私钥加密                 strJiamihou = BCSignUtil.EncryptByKey(strDJM, strPriPkcs8, false, privateKeySize);                 Console.WriteLine("私钥加密后：" + strJiamihou);                  //公钥解密                 strJiemihou = BCSignUtil.DecryptByKey(strJiamihou, strPub, true, privateKeySize);                 Console.WriteLine("公钥解密后：" + strJiemihou);             }             catch (Exception ex)             {                 Console.WriteLine("ex:" + ex.Message);             }              Console.WriteLine("hello END.");             Console.ReadKey();         }     } }