public class CertHelper
    {

        string pfxPath = @"E:\開發輔助專案\cert\taisuyuanqing.pfx";
        string cerPath = @"E:\開發輔助專案\cert\taisuyuanqing.cer";

        #region *從檔案中讀取公鑰和私鑰

        #region +從檔案中讀取公鑰
        /// <summary>
        /// 從檔案中讀取公鑰
        /// </summary>
        ///
 
 <returns></returns>
        public string GetPlulicKey()
        {
            try
            {
                X509Certificate2 x509 = new X509Certificate2(cerPath);
                return x509.PublicKey.Key.ToXmlString(false);
            }
            catch (Exception ex)
            {
                
 
return string.Empty;
            }
        }
        #endregion

        #region +從私鑰檔案中讀取私鑰
        /// <summary>
        /// 從私鑰檔案中讀取私鑰
        /// </summary>
        public void GetPrivateKey()
        {
            try
            {
                X509Certificate2 x509 = new X509Certificate2(pfxPath, "
 
123456", X509KeyStorageFlags.Exportable);
                var publicKey = x509.PublicKey.Key.ToXmlString(false);
                var privateKey = x509.PrivateKey.ToXmlString(true);

                var str = "逍遙帝君 15210253 xiaoyaodijun";

                var result = RSAHelper.RSAEncrypt(publicKey, str);
                var content = RSAHelper.RSADecrypt(privateKey, result);
            }
            catch (Exception)
            {

                throw;
            }
        }
        #endregion

        #endregion



        #region + 從證書庫中獲取證書
        /// <summary>
        /// 從證書庫中獲取證書
        /// </summary>
        /// <param name="subjectName">證書名字</param>
        /// <returns></returns>
        public X509Certificate2 GetCertificateFromStore(string subjectName)
        {
            try
            {
                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;

            }
            catch (Exception)
            {
                throw;
            }
        }
        #endregion

        #region *匯出證書檔案

        #region +從證書庫中匯出私鑰檔案
        /// <summary>     
        /// 從WINDOWS證書儲存區的個人MY區找到主題為subjectName的證書，     
        /// 並匯出為pfx檔案，同時為其指定一個密碼     
        /// 並將證書從個人區刪除(如果isDelFromstor為true)     
        /// </summary>     
        /// <param name="subjectName">證書主題，不包含CN=</param>     
        /// <param name="pfxFileName">pfx檔名</param>     
        /// <param name="password">pfx檔案密碼</param>     
        /// <param name="isDelFromStore">是否從儲存區刪除</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)
                {

                    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())
                            {
                                fileStream.Close();
                                return false;
                            }
                        }
                        fileStream.Close();
                    }
                    if (isDelFromStore == true)
                        store.Remove(x509);
                }
            }
            store.Close();
            store = null;
            storecollection = null;
            return true;
        }
        #endregion

        #region + 從證書庫中匯出公鑰檔案
        /// <summary>
        /// 從證書庫中匯出公鑰檔案
        /// </summary>
        /// <param name="subjectName">證書名字</param>
        /// <param name="cerFileName">存放公鑰的檔案路徑</param>
        public void ExportToCerFile(string subjectName, string cerFileName)
        {
            try
            {
                subjectName = "CN=" + subjectName;
                X509Store store = new X509Store(StoreName.My, StoreLocation.LocalMachine);
                store.Open(OpenFlags.ReadWrite);
                X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
                foreach (X509Certificate2 x509 in storecollection)
                {
                    if (x509.Subject != subjectName) continue;

                    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())
                            {
                                fileStream.Close();

                            }
                        }
                        fileStream.Close();
                    }

                }
            }
            catch (Exception)
            {

                throw;
            }
        }

        #endregion 

        #endregion

        #region + 從證書庫中獲取私鑰和公鑰
        /// <summary>
        /// 從證書庫中獲取私鑰和公鑰
        /// </summary>
        /// <param name="subjectName"></param>
        /// <param name="password"></param>
        /// <returns></returns>
        public string GetPrivateKeyFromStore(string subjectName, string password)
        {
            try
            {
                subjectName = "CN=" + subjectName;
                //CurrentUser=當前使用者   LocalMachine=本地計算機
                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) continue;
                    x509.Export(X509ContentType.Pfx, password);
                    var privateKey = x509.PrivateKey.ToXmlString(true);
                    var publicKey = x509.PublicKey.Key.ToXmlString(false);

                    var str = "逍遙帝君 15210253 xiaoyaodijun";

                    var result = RSAHelper.RSAEncrypt(publicKey, str);
                    var content = RSAHelper.RSADecrypt(privateKey, result);
                }
                return "";
            }
            catch (Exception)
            {
                return "";
            }
        }
        #endregion