C#创建数字证书并导出为pfx，并使用pfx进行非对称加解密

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我的项目当中，考虑到安全性，需要为每个客户端分发一个数字证书，同时使用数字证书中的公私钥来进行数据的加解密。为了完成这个安全模块，特写了如下一个DEMO程序，该DEMO程序包含的功能有：

1：调用.NET2.0的MAKECERT创建含有私钥的数字证书，并存储到个人证书区；

2：将该证书导出为pfx文件，并为其指定一个用来打开pfx文件的password；

3：读取pfx文件，导出pfx中公钥和私钥；

4：用pfx证书中的公钥进行数据的加密，用私钥进行数据的解密；

系统界面：

代码如下：

/// <summary>
        /// 将证书从证书存储区导出，并存储为pfx文件，同时为pfx文件指定打开的密码
        /// 本函数同时也演示如何用公钥进行加密，私钥进行解密
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btn_toPfxFile_Click(object sender, EventArgs e)
        {
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadWrite);
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
            foreach (X509Certificate2 x509 in storecollection)
            {
                if (x509.Subject == "CN=luminji")
                {
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));
                    byte[] pfxByte = x509.Export(X509ContentType.Pfx, "123");
                    using (FileStream  fileStream = new FileStream("luminji.pfx", FileMode.Create))
                    {
                        // Write the data to the file, byte by byte.
                        for (int i = 0; i < pfxByte.Length; i++)
                            fileStream.WriteByte(pfxByte[i]);
                        // Set the stream position to the beginning of the file.
                        fileStream.Seek(0, SeekOrigin.Begin);
                        // Read and verify the data.
                        for (int i = 0; i < fileStream.Length; i++)
                        {
                            if (pfxByte[i] != fileStream.ReadByte())
                            {
                                Debug.Print("Error writing data.");
                                return;
                            }
                        }
                        fileStream.Close();
                        Debug.Print("The data was written to {0} " +
                            "and verified.", fileStream.Name);
                    }
                    string myname = "my name is luminji! and i love huzhonghua!";
                    string enStr = this.RSAEncrypt(x509.PublicKey.Key.ToXmlString(false), myname);
                    MessageBox.Show("密文是：" + enStr);
                    string deStr = this.RSADecrypt(x509.PrivateKey.ToXmlString(true), enStr);
                    MessageBox.Show("明文是：" + deStr);
                }
            }
            store.Close();
            store = null;
            storecollection = null;
        }
        /// <summary>
        /// 创建还有私钥的证书
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btn_createPfx_Click(object sender, EventArgs e)
        {
            string MakeCert = "C://Program Files//Microsoft Visual Studio 8//SDK//v2.0//Bin//makecert.exe";
            string x509Name = "CN=luminji";
            string param = " -pe -ss my -n /"" + x509Name + "/" " ;
            Process p = Process.Start(MakeCert, param);
            p.WaitForExit();
            p.Close();
            MessageBox.Show("over");
        }
        /// <summary>
        /// 从pfx文件读取证书信息
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btn_readFromPfxFile(object sender, EventArgs e)
        {
            X509Certificate2 pc = new X509Certificate2("luminji.pfx", "123");
            MessageBox.Show("name:" + pc.SubjectName.Name);
            MessageBox.Show("public:" + pc.PublicKey.ToString());
            MessageBox.Show("private:" + pc.PrivateKey.ToString());
            pc = null;
        }
        /// <summary>
        /// RSA解密
        /// </summary>
        /// <param name="xmlPrivateKey"></param>
        /// <param name="m_strDecryptString"></param>
        /// <returns></returns>
        public string RSADecrypt(string xmlPrivateKey, string m_strDecryptString)
        {
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
            provider.FromXmlString(xmlPrivateKey);
            byte[] rgb = Convert.FromBase64String(m_strDecryptString);
            byte[] bytes = provider.Decrypt(rgb, false);
            return new UnicodeEncoding().GetString(bytes);
        }
        /// <summary>
        /// RSA加密
        /// </summary>
        /// <param name="xmlPublicKey"></param>
        /// <param name="m_strEncryptString"></param>
        /// <returns></returns>
        public string RSAEncrypt(string xmlPublicKey, string m_strEncryptString)
        {
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
            provider.FromXmlString(xmlPublicKey);
            byte[] bytes = new UnicodeEncoding().GetBytes(m_strEncryptString);
            return Convert.ToBase64String(provider.Encrypt(bytes, false));
        }

　　上文是一个示例程序，一个完整的证书工具类如下：

public sealed class DataCertificate
    {
        #region 生成证书
        /// <summary>
        /// 根据指定的证书名和makecert全路径生成证书（包含公钥和私钥，并保存在MY存储区）
        /// </summary>
        /// <param name="subjectName"></param>
        /// <param name="makecertPath"></param>
        /// <returns></returns>
        public static bool CreateCertWithPrivateKey(string subjectName, string makecertPath)
        {
            subjectName = "CN=" + subjectName;
            string param = " -pe -ss my -n /"" + subjectName + "/" ";
            try
            {
                Process p = Process.Start(makecertPath, param);
                p.WaitForExit();
                p.Close();
            }
            catch (Exception e)
            {
                LogRecord.putErrorLog(e.ToString(), "DataCerficate.CreateCertWithPrivateKey");
                return false;
            }
            return true;
        }
        #endregion  
 
        #region 文件导入导出
        /// <summary>
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，
        /// 并导出为pfx文件，同时为其指定一个密码
        /// 并将证书从个人区删除(如果isDelFromstor为true)
        /// </summary>
        /// <param name="subjectName">证书主题，不包含CN=</param>
        /// <param name="pfxFileName">pfx文件名</param>
        /// <param name="password">pfx文件密码</param>
        /// <param name="isDelFromStore">是否从存储区删除</param>
        /// <returns></returns>
        public static bool ExportToPfxFile(string subjectName, string pfxFileName,
            string password, bool isDelFromStore)
        {
            subjectName = "CN=" + subjectName;
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadWrite);
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
            foreach (X509Certificate2 x509 in storecollection)
            {
                if (x509.Subject == subjectName)
                {
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));  
 
                    byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);
                    using (FileStream fileStream = new FileStream(pfxFileName, FileMode.Create))
                    {
                        // Write the data to the file, byte by byte.
                        for (int i = 0; i < pfxByte.Length; i++)
                            fileStream.WriteByte(pfxByte[i]);
                        // Set the stream position to the beginning of the file.
                        fileStream.Seek(0, SeekOrigin.Begin);
                        // Read and verify the data.
                        for (int i = 0; i < fileStream.Length; i++)
                        {
                            if (pfxByte[i] != fileStream.ReadByte())
                            {
                                LogRecord.putErrorLog("Export pfx error while verify the pfx file!", "ExportToPfxFile");
                                fileStream.Close();
                                return false;
                            }
                        }
                        fileStream.Close();
                    }
                    if( isDelFromStore == true)
                        store.Remove(x509);
                }
            }
            store.Close();
            store = null;
            storecollection = null;
            return true;
        }
        /// <summary>
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，
        /// 并导出为CER文件（即，只含公钥的）
        /// </summary>
        /// <param name="subjectName"></param>
        /// <param name="cerFileName"></param>
        /// <returns></returns>
        public static bool ExportToCerFile(string subjectName, string cerFileName)
        {
            subjectName = "CN=" + subjectName;
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadWrite);
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
            foreach (X509Certificate2 x509 in storecollection)
            {
                if (x509.Subject == subjectName)
                {
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));
                    //byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);
                    byte[] cerByte = x509.Export(X509ContentType.Cert);
                    using (FileStream fileStream = new FileStream(cerFileName, FileMode.Create))
                    {
                        // Write the data to the file, byte by byte.
                        for (int i = 0; i < cerByte.Length; i++)
                            fileStream.WriteByte(cerByte[i]);
                        // Set the stream position to the beginning of the file.
                        fileStream.Seek(0, SeekOrigin.Begin);
                        // Read and verify the data.
                        for (int i = 0; i < fileStream.Length; i++)
                        {
                            if (cerByte[i] != fileStream.ReadByte())
                            {
                                LogRecord.putErrorLog("Export CER error while verify the CERT file!", "ExportToCERFile");
                                fileStream.Close();
                                return false;
                            }
                        }
                        fileStream.Close();
                    }
                }
            }
            store.Close();
            store = null;
            storecollection = null;
            return true;
        }
        #endregion  
 
        #region 从证书中获取信息
        /// <summary>
        /// 根据私钥证书得到证书实体，得到实体后可以根据其公钥和私钥进行加解密
        /// 加解密函数使用DEncrypt的RSACryption类
        /// </summary>
        /// <param name="pfxFileName"></param>
        /// <param name="password"></param>
        /// <returns></returns>
        public static X509Certificate2 GetCertificateFromPfxFile(string pfxFileName,
            string password)
        {
            try
            {
                return new X509Certificate2(pfxFileName, password, X509KeyStorageFlags.Exportable);
            }
            catch (Exception e)
            {
                LogRecord.putErrorLog("get certificate from pfx" + pfxFileName + " error:" + e.ToString(),
                    "GetCertificateFromPfxFile");
                return null;
            }
        }
        /// <summary>
        /// 到存储区获取证书
        /// </summary>
        /// <param name="subjectName"></param>
        /// <returns></returns>
        public static X509Certificate2 GetCertificateFromStore(string subjectName)
        {
            subjectName = "CN=" + subjectName;
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadWrite);
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
            foreach (X509Certificate2 x509 in storecollection)
            {
                if (x509.Subject == subjectName)
                {
                    return x509;
                }
            }
            store.Close();
            store = null;
            storecollection = null;
            return null;
        }
        /// <summary>
        /// 根据公钥证书，返回证书实体
        /// </summary>
        /// <param name="cerPath"></param>
        public static X509Certificate2 GetCertFromCerFile(string cerPath)
        {
            try
            {
                return new X509Certificate2(cerPath);
            }
            catch (Exception e)
            {
                LogRecord.putErrorLog(e.ToString(), "DataCertificate.LoadStudentPublicKey");
                return null;
            }
        }
        #endregion
    }