在C#中保存Bouncy Castle生成的密钥对

在用Bouncy Castle的C#版API产生公钥和私钥 中产生了一对密钥对，可以用bouncy caslte提供的API进行保存

公钥方面的3个类，具体代码根据命名空间自行查看其源代码：

Org.BouncyCastle.Asn1.X509 . SubjectPublicKeyInfo

Org.BouncyCastle.X509 . SubjectPublicKeyInfoFactory

Org.BouncyCastle.Security . PublicKeyFactory

用法：

SubjectPublicKeyInfo subInfo = SubjectPublicKeyInfoFactory .CreateSubjectPublicKeyInfo(rsaPublic);

//rsaPublic是产生的公钥，类型是AsymmetricKeyParameter/RsaKeyParameters，其中后者集成前者

AsymmetricKeyParameter testpublicKey = (RsaKeyParameters)PublicKeyFactory. CreateKey(subInfo);

私钥方面，但私钥保存到本地文件中时，可以选择加密保存，3DES with sha1，涉及到5个类：

Org.BouncyCastle.Asn1.Pkcs . PrivateKeyInfo

Org.BouncyCastle.Pkcs . PrivateKeyInfoFactory

Org.BouncyCastle.Security . PrivateKeyFactory

Org.BouncyCastle.Asn1.Pkcs . EncryptedPrivateKeyInfo

Org.BouncyCastle.Pkcs . EncryptedPrivateKeyInfoFactory

前面3个类的用法同上面公钥的类似：

PrivateKeyInfo privInfo = PrivateKeyInfoFactory .CreatePrivateKeyInfo(rsaPrivate);

AsymmetricKeyParameter testResult = (RsaPrivateCrtKeyParameters) PrivateKeyFactory .CreateKey(privInfo);

如果要加密保存私钥的话：

string alg = "1.2.840.113549.1.12.1.3"; // 3 key triple DES with SHA-1
byte[] salt = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int count=1000;
char[] password="123456".ToCharArray();
EncryptedPrivateKeyInfo enPrivateKeyInfo = EncryptedPrivateKeyInfoFactory .CreateEncryptedPrivateKeyInfo(
    alg,
    password,
    salt,
    count,
    privateKey);

从EncryptedPrivateKeyInfo 恢复出PrivateKeyInfo 则简单多了：

PrivateKeyInfo priInfo = PrivateKeyInfoFactory .CreatePrivateKeyInfo(password, enPrivateKeyInfo);

再导出私钥：

AsymmetricKeyParameter privateKey = PrivateKeyFactory .CreateKey(priInfo);

SubjectPublicKeyInfo和PrivateKeyInfo都提供了ToAsn1Object()方法，转换成很Asn1Object，再使用GetEncoded()方法，生成byte数组，然后保存到本地。编码是BER，当然DER也是可以。从本地读取文件时逆过程即可，把读取到的byte数组转换成Asn1Object对象，再使用GetInstance()方法。

测试代码：

1. using System;
2. using System.Collections.Generic;
3. using System.Collections;
4. using System.Text;
5. using System.Security.Cryptography;
6. using System.Security.Cryptography.X509Certificates;    // X509Certificate2
7. using System.IO;
8. using Org.BouncyCastle.Crypto.Generators;
9. using Org.BouncyCastle.Crypto.Parameters;
10. using Org.BouncyCastle.Crypto;
11. using Org.BouncyCastle.Security;
12. using Org.BouncyCastle.Crypto.Engines;  //IAsymmetricBlockCipher engine = new RsaEngine();
13. using Org.BouncyCastle.Math;
14. using Org.BouncyCastle.Asn1.X509; //X509Name
15. using Org.BouncyCastle.X509;
16. using Org.BouncyCastle.Utilities.Collections;   //X509V3CertificateGenerator
17. using Org.BouncyCastle.Asn1.Pkcs;   //PrivateKeyInfo
18. using Org.BouncyCastle.Pkcs;
19. using Org.BouncyCastle.Asn1;
20. namespace ConsoleApplication1
21. {
22. class Program
23. {
24. static void Main(string[] args)
25. {
26. //公钥和密钥的生成，并加密解密测试
27. RsaKeyGeneratorTest();    //done!!!!!
28. }
29. private static void RsaKeyGeneratorTest()
30. {
31. //RSA密钥对的构造器
32. RsaKeyPairGenerator keyGenerator = new RsaKeyPairGenerator();
33. //RSA密钥构造器的参数
34. RsaKeyGenerationParameters param = new RsaKeyGenerationParameters(
35. Org.BouncyCastle.Math.BigInteger.ValueOf(3),
36. new Org.BouncyCastle.Security.SecureRandom(),
37. 1024,   //密钥长度
38. 25);
39. //用参数初始化密钥构造器
40. keyGenerator.Init(param);
41. //产生密钥对
42. AsymmetricCipherKeyPair keyPair = keyGenerator.GenerateKeyPair();
43. //获取公钥和私钥
44. AsymmetricKeyParameter publicKey = keyPair.Public;
45. AsymmetricKeyParameter privateKey = keyPair.Private;
46. if (((RsaKeyParameters)publicKey).Modulus.BitLength < 1024)
47. {
48. Console.WriteLine("failed key generation (1024) length test");
49. }
50. savetheKey(publicKey, privateKey);
51. //一个测试……………………
52. //输入，十六进制的字符串，解码为byte[]
53. //string input = "4e6f77206973207468652074696d6520666f7220616c6c20676f6f64206d656e";
54. //byte[] testData = Org.BouncyCastle.Utilities.Encoders.Hex.Decode(input);
55. string input = "popozh RSA test";
56. byte[] testData = Encoding.UTF8.GetBytes(input);
57. //非对称加密算法，加解密用
58. IAsymmetricBlockCipher engine = new RsaEngine();
59. //公钥加密
60. //从保存在本地的磁盘文件中读取公钥
61. Asn1Object aobject = Asn1Object.FromStream(new FileStream(@"E:/Desktop/a.pub",FileMode.Open,FileAccess.Read));  //a.puk??
62. SubjectPublicKeyInfo pubInfo = SubjectPublicKeyInfo.GetInstance(aobject);
63. AsymmetricKeyParameter testpublicKey = (RsaKeyParameters)PublicKeyFactory.CreateKey(pubInfo);
64. FileStream fs;
65. engine.Init(true, testpublicKey);
66. try
67. {
68. //Console.WriteLine("加密前:" + Convert.ToBase64String(testData) + Environment.NewLine);
69. testData = engine.ProcessBlock(testData, 0, testData.Length);
70. Console.WriteLine("加密完成！" + Environment.NewLine);
71. fs = new FileStream(@"E:/Desktop/encryptedBytes", FileMode.Create, FileAccess.Write);
72. fs.Write(testData, 0, testData.Length);
73. fs.Close();
74. Console.WriteLine("保存密文成功" + Environment.NewLine);
75. }
76. catch (Exception ex)
77. {
78. Console.WriteLine("failed - exception " + Environment.NewLine + ex.ToString());
79. }
80. //私钥解密
81. //获取加密的私钥，进行解密，获得私钥
82. fs = new FileStream(@"E:/Desktop/encryptedBytes", FileMode.Open, FileAccess.Read);
83. byte[] anothertestdata = new byte[1024];
84. fs.Read(anothertestdata, 0, anothertestdata.Length);
85. fs.Close();
86. Asn1Object aobj = Asn1Object.FromStream(new FileStream(@"E:/Desktop/a.pri", FileMode.Open, FileAccess.Read));   //a.pvk??
87. EncryptedPrivateKeyInfo enpri = EncryptedPrivateKeyInfo.GetInstance(aobj);
88. char[] password = "123456".ToCharArray();
89. PrivateKeyInfo priKey = PrivateKeyInfoFactory.CreatePrivateKeyInfo(password, enpri);    //解密
90. AsymmetricKeyParameter anotherprivateKey = PrivateKeyFactory.CreateKey(priKey);    //私钥
91. engine.Init(false, anotherprivateKey);
92. try
93. {
94. anothertestdata = engine.ProcessBlock(anothertestdata, 0, testData.Length);
95. Console.WriteLine("解密后密文为：" + Encoding.UTF8.GetString(anothertestdata) + Environment.NewLine);
96. }
97. catch (Exception e)
98. {
99. Console.WriteLine("failed - exception " + e.ToString());
100. }
101. Console.Read();
102. }
103. private static void savetheKey(AsymmetricKeyParameter publicKey, AsymmetricKeyParameter privateKey)
104. {
105. //保存公钥到文件
106. SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(publicKey);
107. Asn1Object aobject = publicKeyInfo.ToAsn1Object();
108. byte[] pubInfoByte = aobject.GetEncoded();
109. FileStream fs = new FileStream(@"E:/Desktop/a.pub", FileMode.Create, FileAccess.Write);
110. fs.Write(pubInfoByte, 0, pubInfoByte.Length);
111. fs.Close();
112. //保存私钥到文件
113. /*
114. PrivateKeyInfo privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(privateKey);
115. aobject = privateKeyInfo.ToAsn1Object();
116. byte[] priInfoByte = aobject.GetEncoded();
117. fs = new FileStream(@"E:/Desktop/a.pri", FileMode.Create, FileAccess.Write);
118. fs.Write(priInfoByte, 0, priInfoByte.Length);
119. fs.Close();
120. */
121. string alg = "1.2.840.113549.1.12.1.3"; // 3 key triple DES with SHA-1
122. byte[] salt = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
123. int count=1000;
124. char[] password="123456".ToCharArray();
125. EncryptedPrivateKeyInfo enPrivateKeyInfo = EncryptedPrivateKeyInfoFactory.CreateEncryptedPrivateKeyInfo(
126. alg,
127. password,
128. salt,
129. count,
130. privateKey);
131. byte[] priInfoByte = enPrivateKeyInfo.ToAsn1Object().GetEncoded();
132. fs = new FileStream(@"E:/Desktop/a.pri", FileMode.Create, FileAccess.Write);
133. fs.Write(priInfoByte, 0, priInfoByte.Length);
134. fs.Close();
135. //还原
136. //PrivateKeyInfo priInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(password, enPrivateKeyInfo);
137. //AsymmetricKeyParameter privateKey = PrivateKeyFactory.CreateKey(priInfoByte);
138. }
139. }
140. }

接下来就可以生成cer公钥证书或者pfx证书