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. }