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  
 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 }