C#.NET Framework 使用BC库（BouncyCastle） RSA 私钥签名 公钥验签（验证签名） ver:20230704

C#.NET Framework 使用BC库（BouncyCastle） RSA 私钥签名 公钥验签（验证签名） ver:20230704

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。

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

关键代码：

BC库，私钥转换，默认支持PKCS8：

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;
        }

公钥转换：

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;
        }

BCSignUtil 辅助类，nuget 中引用 Portable.BouncyCastle。

using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Security;
using System;
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;
        }

    }
}

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 = "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";
                //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
            }
            catch (Exception ex)
            {
                Console.WriteLine("ex:" + ex.Message);
            }

            Console.WriteLine("hello END.");
            Console.ReadKey();
        }
    }
}

。