Java RSA 生成公钥 私钥

目前为止，RSA是应用最多的公钥加密算法，能够抵抗已知的绝大多数密码攻击，已被ISO推荐为公钥数据加密标准。

RSA算法中，每个通信主体都有两个钥匙，一个公钥（Public Key）用来对数据进行加密； 一个私钥（Private Key）用来对数据进行解密。 

下面来看下Java中是如何使用KeyPairGenerator生成keyMap 并从中解析出PublickKey和PrivateKey的。

1.  

2. 完整代码：

   import java.security.Key;

   import java.security.KeyPair;

   import java.security.KeyPairGenerator;

   import java.security.interfaces.RSAPrivateKey;

   import java.security.interfaces.RSAPublicKey;

   import java.util.HashMap;

   import java.util.Map; 

   import sun.misc.BASE64Decoder;  

   import sun.misc.BASE64Encoder;

   @SuppressWarnings("unused")

   public class Keys {

       public static final String KEY_ALGORITHM = "RSA";

       public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

       private static final String PUBLIC_KEY = "RSAPublicKey";

       private static final String PRIVATE_KEY = "RSAPrivateKey";

    

   public static void main(String[] args) {

   Map<String, Object> keyMap;

   try {

   keyMap = initKey();

   String publicKey =  getPublicKey(keyMap);

   System.out.println(publicKey);

   String privateKey =  getPrivateKey(keyMap);

   System.out.println(privateKey);

   } catch (Exception e) { 

   e.printStackTrace();

   }  

   }

   public static String getPublicKey(Map<String, Object> keyMap) throws Exception {

            Key key = (Key) keyMap.get(PUBLIC_KEY); 

            byte[] publicKey = key.getEncoded(); 

   return encryptBASE64(key.getEncoded());

   }

   public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {

            Key key = (Key) keyMap.get(PRIVATE_KEY); 

            byte[] privateKey =key.getEncoded(); 

   return encryptBASE64(key.getEncoded());

   }  

              

       public static byte[] decryptBASE64(String key) throws Exception {               

           return (new BASE64Decoder()).decodeBuffer(key);               

       }                                 

                  

       public static String encryptBASE64(byte[] key) throws Exception {               

           return (new BASE64Encoder()).encodeBuffer(key);               

       }       

       

   public static Map<String, Object> initKey() throws Exception {

   KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);

   keyPairGen.initialize(1024);

   KeyPair keyPair = keyPairGen.generateKeyPair();

   RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

   RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

   Map<String, Object> keyMap = new HashMap<String, Object>(2);

   keyMap.put(PUBLIC_KEY, publicKey);

   keyMap.put(PRIVATE_KEY, privateKey);

   return keyMap;

   }

   }

3. 2

   测试结果：