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：
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
21 namespace ConsoleApplication1
22 {
23 class Program
24 {
25 static void Main(string[] args)
26 {
27 //公钥和密钥的生成，并加密解密测试
28 RsaKeyGeneratorTest(); //done!!!!!
29
30 }
31 private static void RsaKeyGeneratorTest()
32 {
33 //RSA密钥对的构造器
34 RsaKeyPairGenerator keyGenerator = new RsaKeyPairGenerator();
35 //RSA密钥构造器的参数
36 RsaKeyGenerationParameters param = new RsaKeyGenerationParameters(
37 Org.BouncyCastle.Math.BigInteger.ValueOf(3),
38 new Org.BouncyCastle.Security.SecureRandom(),
39 1024, //密钥长度
40 25);
41 //用参数初始化密钥构造器
42 keyGenerator.Init(param);
43 //产生密钥对
44 AsymmetricCipherKeyPair keyPair = keyGenerator.GenerateKeyPair();
45 //获取公钥和私钥
46 AsymmetricKeyParameter publicKey = keyPair.Public;
47 AsymmetricKeyParameter privateKey = keyPair.Private;
48
49 if (((RsaKeyParameters)publicKey).Modulus.BitLength < 1024)
50 {
51 Console.WriteLine("failed key generation (1024) length test");
52 }
53 savetheKey(publicKey, privateKey);
54
55
56 //一个测试……………………
57 //输入，十六进制的字符串，解码为byte[]
58 //string input = "4e6f77206973207468652074696d6520666f7220616c6c20676f6f64206d656e";
59 //byte[] testData = Org.BouncyCastle.Utilities.Encoders.Hex.Decode(input);
60 string input = "popozh RSA test";
61 byte[] testData = Encoding.UTF8.GetBytes(input);
62 //非对称加密算法，加解密用
63 IAsymmetricBlockCipher engine = new RsaEngine();
64 //公钥加密
65 //从保存在本地的磁盘文件中读取公钥
66 Asn1Object aobject = Asn1Object.FromStream(new FileStream(@"E:/Desktop/a.pub",FileMode.Open,FileAccess.Read)); //a.puk??
67 SubjectPublicKeyInfo pubInfo = SubjectPublicKeyInfo.GetInstance(aobject);
68 AsymmetricKeyParameter testpublicKey = (RsaKeyParameters)PublicKeyFactory.CreateKey(pubInfo);
69 FileStream fs;
70 engine.Init(true, testpublicKey);
71 try
72 {
73 //Console.WriteLine("加密前:" + Convert.ToBase64String(testData) + Environment.NewLine);
74 testData = engine.ProcessBlock(testData, 0, testData.Length);
75 Console.WriteLine("加密完成！" + Environment.NewLine);
76 fs = new FileStream(@"E:/Desktop/encryptedBytes", FileMode.Create, FileAccess.Write);
77 fs.Write(testData, 0, testData.Length);
78 fs.Close();
79 Console.WriteLine("保存密文成功" + Environment.NewLine);
80 }
81 catch (Exception ex)
82 {
83 Console.WriteLine("failed - exception " + Environment.NewLine + ex.ToString());
84 }
85 //私钥解密
86 //获取加密的私钥，进行解密，获得私钥
87 fs = new FileStream(@"E:/Desktop/encryptedBytes", FileMode.Open, FileAccess.Read);
88 byte[] anothertestdata = new byte[1024];
89 fs.Read(anothertestdata, 0, anothertestdata.Length);
90 fs.Close();
91 Asn1Object aobj = Asn1Object.FromStream(new FileStream(@"E:/Desktop/a.pri", FileMode.Open, FileAccess.Read)); //a.pvk??
92 EncryptedPrivateKeyInfo enpri = EncryptedPrivateKeyInfo.GetInstance(aobj);
93 char[] password = "123456".ToCharArray();
94 PrivateKeyInfo priKey = PrivateKeyInfoFactory.CreatePrivateKeyInfo(password, enpri); //解密
95 AsymmetricKeyParameter anotherprivateKey = PrivateKeyFactory.CreateKey(priKey); //私钥
96 engine.Init(false, anotherprivateKey);
97 try
98 {
99 anothertestdata = engine.ProcessBlock(anothertestdata, 0, testData.Length);
100 Console.WriteLine("解密后密文为：" + Encoding.UTF8.GetString(anothertestdata) + Environment.NewLine);
101 }
102 catch (Exception e)
103 {
104 Console.WriteLine("failed - exception " + e.ToString());
105 }
106
107 Console.Read();
108
109 }
110 private static void savetheKey(AsymmetricKeyParameter publicKey, AsymmetricKeyParameter privateKey)
111 {
112 //保存公钥到文件
113 SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(publicKey);
114 Asn1Object aobject = publicKeyInfo.ToAsn1Object();
115 byte[] pubInfoByte = aobject.GetEncoded();
116 FileStream fs = new FileStream(@"E:/Desktop/a.pub", FileMode.Create, FileAccess.Write);
117 fs.Write(pubInfoByte, 0, pubInfoByte.Length);
118 fs.Close();
119 //保存私钥到文件
120 /*
121 PrivateKeyInfo privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(privateKey);
122 aobject = privateKeyInfo.ToAsn1Object();
123 byte[] priInfoByte = aobject.GetEncoded();
124 fs = new FileStream(@"E:/Desktop/a.pri", FileMode.Create, FileAccess.Write);
125 fs.Write(priInfoByte, 0, priInfoByte.Length);
126 fs.Close();
127 */
128 string alg = "1.2.840.113549.1.12.1.3"; // 3 key triple DES with SHA-1
129 byte[] salt = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
130 int count=1000;
131 char[] password="123456".ToCharArray();
132 EncryptedPrivateKeyInfo enPrivateKeyInfo = EncryptedPrivateKeyInfoFactory.CreateEncryptedPrivateKeyInfo(
133 alg,
134 password,
135 salt,
136 count,
137 privateKey);
138 byte[] priInfoByte = enPrivateKeyInfo.ToAsn1Object().GetEncoded();
139 fs = new FileStream(@"E:/Desktop/a.pri", FileMode.Create, FileAccess.Write);
140 fs.Write(priInfoByte, 0, priInfoByte.Length);
141 fs.Close();
142 //还原
143 //PrivateKeyInfo priInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(password, enPrivateKeyInfo);
144 //AsymmetricKeyParameter privateKey = PrivateKeyFactory.CreateKey(priInfoByte);
145 }
146 }
147 }