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：
01./// <summary> 02. /// 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 03. /// 本函数同时也演示如何用公钥进行加密，私钥进行解密 04. /// </summary> 05. /// <param name="sender"></param> 06. /// <param name="e"></param> 07. private void btn_toPfxFile_Click(object sender, EventArgs e) 08. { 09. X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser); 10. store.Open(OpenFlags.ReadWrite); 11. X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates; 12. foreach (X509Certificate2 x509 in storecollection) 13. { 14. if (x509.Subject == "CN=luminji") 15. { 16. Debug.Print(string.Format("certificate name: {0}", x509.Subject)); 17. byte[] pfxByte = x509.Export(X509ContentType.Pfx, "123"); 18. using (FileStream fileStream = new FileStream("luminji.pfx", FileMode.Create)) 19. { 20. // Write the data to the file, byte by byte. 21. for (int i = 0; i < pfxByte.Length; i++) 22. fileStream.WriteByte(pfxByte[i]); 23. // Set the stream position to the beginning of the file. 24. fileStream.Seek(0, SeekOrigin.Begin); 25. // Read and verify the data. 26. for (int i = 0; i < fileStream.Length; i++) 27. { 28. if (pfxByte[i] != fileStream.ReadByte()) 29. { 30. Debug.Print("Error writing data."); 31. return; 32. } 33. } 34. fileStream.Close(); 35. Debug.Print("The data was written to {0} " + 36. "and verified.", fileStream.Name); 37. } 38. string myname = "my name is luminji! and i love huzhonghua!"; 39. string enStr = this.RSAEncrypt(x509.PublicKey.Key.ToXmlString(false), myname); 40. MessageBox.Show("密文是：" + enStr); 41. string deStr = this.RSADecrypt(x509.PrivateKey.ToXmlString(true), enStr); 42. MessageBox.Show("明文是：" + deStr); 43. } 44. } 45. store.Close(); 46. store = null; 47. storecollection = null; 48. } 49. /// <summary> 50. /// 创建还有私钥的证书 51. /// </summary> 52. /// <param name="sender"></param> 53. /// <param name="e"></param> 54. private void btn_createPfx_Click(object sender, EventArgs e) 55. { 56. string MakeCert = "C:\\Program Files\\Microsoft Visual Studio 8\\SDK\\v2.0\\Bin\\makecert.exe"; 57. string x509Name = "CN=luminji"; 58. string param = " -pe -ss my -n \"" + x509Name + "\" " ; 59. Process p = Process.Start(MakeCert, param); 60. p.WaitForExit(); 61. p.Close(); 62. MessageBox.Show("over"); 63. } 64. /// <summary> 65. /// 从pfx文件读取证书信息 66. /// </summary> 67. /// <param name="sender"></param> 68. /// <param name="e"></param> 69. private void btn_readFromPfxFile(object sender, EventArgs e) 70. { 71. X509Certificate2 pc = new X509Certificate2("luminji.pfx", "123"); 72. MessageBox.Show("name:" + pc.SubjectName.Name); 73. MessageBox.Show("public:" + pc.PublicKey.ToString()); 74. MessageBox.Show("private:" + pc.PrivateKey.ToString()); 75. pc = null; 76. } 77. /// <summary> 78. /// RSA解密 79. /// </summary> 80. /// <param name="xmlPrivateKey"></param> 81. /// <param name="m_strDecryptString"></param> 82. /// <returns></returns> 83. public string RSADecrypt(string xmlPrivateKey, string m_strDecryptString) 84. { 85. RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 86. provider.FromXmlString(xmlPrivateKey); 87. byte[] rgb = Convert.FromBase64String(m_strDecryptString); 88. byte[] bytes = provider.Decrypt(rgb, false); 89. return new UnicodeEncoding().GetString(bytes); 90. } 91. /// <summary> 92. /// RSA加密 93. /// </summary> 94. /// <param name="xmlPublicKey"></param> 95. /// <param name="m_strEncryptString"></param> 96. /// <returns></returns> 97. public string RSAEncrypt(string xmlPublicKey, string m_strEncryptString) 98. { 99. RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 100. provider.FromXmlString(xmlPublicKey); 101. byte[] bytes = new UnicodeEncoding().GetBytes(m_strEncryptString); 102. return Convert.ToBase64String(provider.Encrypt(bytes, false)); 103. }
上文是一个示例程序，一个完整的证书工具类如下：
01.public sealed class DataCertificate 02. { 03. #region 生成证书 04. /// <summary> 05. /// 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） 06. /// </summary> 07. /// <param name="subjectName"></param> 08. /// <param name="makecertPath"></param> 09. /// <returns></returns> 10. public static bool CreateCertWithPrivateKey(string subjectName, string makecertPath) 11. { 12. subjectName = "CN=" + subjectName; 13. string param = " -pe -ss my -n \"" + subjectName + "\" "; 14. try 15. { 16. Process p = Process.Start(makecertPath, param); 17. p.WaitForExit(); 18. p.Close(); 19. } 20. catch (Exception e) 21. { 22. LogRecord.putErrorLog(e.ToString(), "DataCerficate.CreateCertWithPrivateKey"); 23. return false; 24. } 25. return true; 26. } 27. #endregion 28. 29. #region 文件导入导出 30. /// <summary> 31. /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书， 32. /// 并导出为pfx文件，同时为其指定一个密码 33. /// 并将证书从个人区删除(如果isDelFromstor为true) 34. /// </summary> 35. /// <param name="subjectName">证书主题，不包含CN=</param> 36. /// <param name="pfxFileName">pfx文件名</param> 37. /// <param name="password">pfx文件密码</param> 38. /// <param name="isDelFromStore">是否从存储区删除</param> 39. /// <returns></returns> 40. public static bool ExportToPfxFile(string subjectName, string pfxFileName, 41. string password, bool isDelFromStore) 42. { 43. subjectName = "CN=" + subjectName; 44. X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser); 45. store.Open(OpenFlags.ReadWrite); 46. X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates; 47. foreach (X509Certificate2 x509 in storecollection) 48. { 49. if (x509.Subject == subjectName) 50. { 51. Debug.Print(string.Format("certificate name: {0}", x509.Subject)); 52. 53. byte[] pfxByte = x509.Export(X509ContentType.Pfx, password); 54. using (FileStream fileStream = new FileStream(pfxFileName, FileMode.Create)) 55. { 56. // Write the data to the file, byte by byte. 57. for (int i = 0; i < pfxByte.Length; i++) 58. fileStream.WriteByte(pfxByte[i]); 59. // Set the stream position to the beginning of the file. 60. fileStream.Seek(0, SeekOrigin.Begin); 61. // Read and verify the data. 62. for (int i = 0; i < fileStream.Length; i++) 63. { 64. if (pfxByte[i] != fileStream.ReadByte()) 65. { 66. LogRecord.putErrorLog("Export pfx error while verify the pfx file!", "ExportToPfxFile"); 67. fileStream.Close(); 68. return false; 69. } 70. } 71. fileStream.Close(); 72. } 73. if( isDelFromStore == true) 74. store.Remove(x509); 75. } 76. } 77. store.Close(); 78. store = null; 79. storecollection = null; 80. return true; 81. } 82. /// <summary> 83. /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书， 84. /// 并导出为CER文件（即，只含公钥的） 85. /// </summary> 86. /// <param name="subjectName"></param> 87. /// <param name="cerFileName"></param> 88. /// <returns></returns> 89. public static bool ExportToCerFile(string subjectName, string cerFileName) 90. { 91. subjectName = "CN=" + subjectName; 92. X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser); 93. store.Open(OpenFlags.ReadWrite); 94. X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates; 95. foreach (X509Certificate2 x509 in storecollection) 96. { 97. if (x509.Subject == subjectName) 98. { 99. Debug.Print(string.Format("certificate name: {0}", x509.Subject)); 100. //byte[] pfxByte = x509.Export(X509ContentType.Pfx, password); 101. byte[] cerByte = x509.Export(X509ContentType.Cert); 102. using (FileStream fileStream = new FileStream(cerFileName, FileMode.Create)) 103. { 104. // Write the data to the file, byte by byte. 105. for (int i = 0; i < cerByte.Length; i++) 106. fileStream.WriteByte(cerByte[i]); 107. // Set the stream position to the beginning of the file. 108. fileStream.Seek(0, SeekOrigin.Begin); 109. // Read and verify the data. 110. for (int i = 0; i < fileStream.Length; i++) 111. { 112. if (cerByte[i] != fileStream.ReadByte()) 113. { 114. LogRecord.putErrorLog("Export CER error while verify the CERT file!", "ExportToCERFile"); 115. fileStream.Close(); 116. return false; 117. } 118. } 119. fileStream.Close(); 120. } 121. } 122. } 123. store.Close(); 124. store = null; 125. storecollection = null; 126. return true; 127. } 128. #endregion 129. 130. #region 从证书中获取信息 131. /// <summary> 132. /// 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 133. /// 加解密函数使用DEncrypt的RSACryption类 134. /// </summary> 135. /// <param name="pfxFileName"></param> 136. /// <param name="password"></param> 137. /// <returns></returns> 138. public static X509Certificate2 GetCertificateFromPfxFile(string pfxFileName, 139. string password) 140. { 141. try 142. { 143. return new X509Certificate2(pfxFileName, password, X509KeyStorageFlags.Exportable); 144. } 145. catch (Exception e) 146. { 147. LogRecord.putErrorLog("get certificate from pfx" + pfxFileName + " error:" + e.ToString(), 148. "GetCertificateFromPfxFile"); 149. return null; 150. } 151. } 152. /// <summary> 153. /// 到存储区获取证书 154. /// </summary> 155. /// <param name="subjectName"></param> 156. /// <returns></returns> 157. public static X509Certificate2 GetCertificateFromStore(string subjectName) 158. { 159. subjectName = "CN=" + subjectName; 160. X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser); 161. store.Open(OpenFlags.ReadWrite); 162. X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates; 163. foreach (X509Certificate2 x509 in storecollection) 164. { 165. if (x509.Subject == subjectName) 166. { 167. return x509; 168. } 169. } 170. store.Close(); 171. store = null; 172. storecollection = null; 173. return null; 174. } 175. /// <summary> 176. /// 根据公钥证书，返回证书实体 177. /// </summary> 178. /// <param name="cerPath"></param> 179. public static X509Certificate2 GetCertFromCerFile(string cerPath) 180. { 181. try 182. { 183. return new X509Certificate2(cerPath); 184. } 185. catch (Exception e) 186. { 187. LogRecord.putErrorLog(e.ToString(), "DataCertificate.LoadStudentPublicKey"); 188. return null; 189. } 190. } 191. #endregion 192. }
