我的專案當中，考慮到安全性，需要為每個客戶端分發一個數字證書，同時使用數字證書中的公私鑰來進行資料的加解密。為了完成這個安全模組，特寫了如下一個DEMO程式，該DEMO程式包含的功能有：

1：呼叫.NET2.0的MAKECERT建立含有私鑰的數字證書，並存儲到個人證書區；

2：將該證書匯出為pfx檔案，併為其指定一個用來開啟pfx檔案的password；

3：讀取pfx檔案，匯出pfx中公鑰和私鑰；

4：用pfx證書中的公鑰進行資料的加密，用私鑰進行資料的解密；

系統介面：

程式碼如下：

/// <summary> /// 將證書從證書儲存區匯出，並存儲為pfx檔案，同時為pfx檔案指定開啟的密碼 /// 本函式同時也演示如何用公鑰進行加密，私鑰進行解密 /// </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> /// 建立還有私鑰的證書 /// </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> /// 從pfx檔案讀取證書資訊 /// </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)); }

上文是一個示例程式，一個完整的證書工具類如下：

public sealed class DataCertificate { #region 生成證書 /// <summary> /// 根據指定的證書名和makecert全路徑生成證書（包含公鑰和私鑰，並儲存在MY儲存區） /// </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 檔案匯入匯出 /// <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) { 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> /// 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CER檔案（即，只含公鑰的） /// </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 從證書中獲取資訊 /// <summary> /// 根據私鑰證書得到證書實體，得到實體後可以根據其公鑰和私鑰進行加解密 /// 加解密函式使用DEncrypt的RSACryption類 /// </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> /// 到儲存區獲取證書 /// </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> /// 根據公鑰證書，返回證書實體 /// </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 }