RSA非对称加密解密例子

------要加密的内容

    String encryptText = "encryptText";

    keyPairGen.initialize(1024);

    KeyPair keyPair = keyPairGen.generateKeyPair();

    // Generate keys

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

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

    //存放公钥密钥路径。

    FileOutputStream pubfos = new FileOutputStream("E:/xlmPublicKey.dat");

    ObjectOutputStream puboos = new ObjectOutputStream(pubfos);

    //生成公钥密钥

    puboos.writeObject(publicKey);

    puboos.close();

    

    //保存私钥文件

    FileOutputStream prifos = new FileOutputStream("E:/xlmPrivateKey.dat");

    ObjectOutputStream prioos = new ObjectOutputStream(prifos);

    prioos.writeObject(privateKey);

    prioos.close();
   

---------采用公钥进行加密

    byte[] e = encrypt.encrypt2(privateKey, encryptText.getBytes());

    byte[] de = encrypt.decrypt2(publicKey, e);

    System.out.println(encrypt.bytesToString(e));

    System.out.println(encrypt.bytesToString(de));

    

    //保存密文

    FileOutputStream lfos = new FileOutputStream("E:/license.dat");

    DataOutputStream ldos=new DataOutputStream(lfos);

    ldos.write(e);
    ldos.close();

解密：

RSAEncrypt encrypt = new RSAEncrypt();

            // 生成实现指定摘要算法的 KeyPairGenerator 对象。RSA摘要

            KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");

            

            FileInputStream pubfis = new FileInputStream("E:/xlmPublicKey.dat");

            ObjectInputStream puboos = new ObjectInputStream(pubfis);

            //生成公钥密钥

            RSAPublicKey pk=(RSAPublicKey)puboos.readObject();

            puboos.close();

            

            

            byte[] b = new byte[128];

            int len = 0;

            FileInputStream lfis = new FileInputStream("E:/license.dat");

            DataInputStream ldos=new DataInputStream(lfis);

            

            while ((len = ldos.read(b)) != -1) {

                ldos.read(b, 0, len);

            }

            byte[] de = encrypt.decrypt2(pk, b);

            System.out.println(encrypt.bytesToString(de));

/**

* 私钥加密

*

* @return byte[]

*/

protected byte[] encrypt2(RSAPrivateKey privateKey, byte[] obj) {

   if (privateKey != null) {

    try {

     Cipher cipher = Cipher.getInstance("RSA");

//     ENCRYPT_MODE : 用于将 cipher 初始化为加密模式的常量。

     cipher.init(Cipher.ENCRYPT_MODE, privateKey);

     return cipher.doFinal(obj);

    } catch (Exception e) {

     e.printStackTrace();

    }

   }

   return null;

}

/**

* Basic decrypt method 公钥解密

*

* @return byte[]

*/

protected byte[] decrypt2(RSAPublicKey publicKey, byte[] obj) {

   if (publicKey != null) {

    try {

     Cipher cipher = Cipher.getInstance("RSA");

//     DECRYPT_MODE : 用于将 cipher 初始化为解密模式的常量。

     cipher.init(Cipher.DECRYPT_MODE, publicKey);

     return cipher.doFinal(obj);

    } catch (Exception e) {

     e.printStackTrace();

    }

   }

   return null;

}