Java RSA 生成公鑰 私鑰

目前為止，RSA是應用最多的公鑰加密算法，能夠抵抗已知的絕大多數密碼攻擊，已被ISO推薦為公鑰數據加密標准。

 

RSA算法中，每個通信主體都有兩個鑰匙，一個公鑰（Public Key）用來對數據進行加密； 一個私鑰（Private Key）用來對數據進行解密。 

 

下面來看下Java中是如何使用KeyPairGenerator生成keyMap 並從中解析出PublickKey和PrivateKey的。

 

1.  

2. 完整代碼：

   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

   測試結果：

   

4.