Java加密/解密之非对称加密算法

比较常见的是RSA(适用于对少量数据加密)和DSA(一般用于数字签名中)。

 

Java使用RSA加密解密：

package com.security.example.example4;

 

import java.security.InvalidKeyException;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.NoSuchAlgorithmException;

import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;

 

import javax.crypto.BadPaddingException;

import javax.crypto.Cipher;

import javax.crypto.IllegalBlockSizeException;

import javax.crypto.NoSuchPaddingException;

 

public class RSA {

// 完成加密/解密工作

private Cipher cipher = null;

// 公钥

private RSAPublicKey rsaPublicKey = null;

// 私钥

private RSAPrivateKey rsaPrivateKey = null;

 

public RSA() {

try {

cipher = Cipher.getInstance("rsa");

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

KeyPair keypair = keyPairGen.genKeyPair();

rsaPrivateKey = (RSAPrivateKey) keypair.getPrivate();

rsaPublicKey = (RSAPublicKey) keypair.getPublic();

} catch (NoSuchAlgorithmException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchPaddingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

 

/**

* 使用私钥加密。

* @param msg:要加密的消息。

* @return加密后的密文

*/

public byte[] encryp(String msg) {

try {

cipher.init(Cipher.ENCRYPT_MODE, rsaPrivateKey);

byte[] encrypMsg = cipher.doFinal(msg.getBytes());

return encrypMsg;

} catch (InvalidKeyException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalBlockSizeException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (BadPaddingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

 

/**

* 使用公钥解密。

* @param msg:密文

* @return解密后的原文

*/

public byte[] decryp(byte[] msg) {

try {

cipher.init(Cipher.DECRYPT_MODE, rsaPublicKey);

byte[] decrypMsg = cipher.doFinal(msg);

return decrypMsg;

} catch (InvalidKeyException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalBlockSizeException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (BadPaddingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

/**

* @param args

*/

public static void main(String[] args) {

String msg = "java安全编程——RSA";

System.out.println("原文是：" + msg);

RSA rsa = new RSA();

byte[] enMsg = rsa.encryp(msg);

System.out.println("加密后是：" + new String(enMsg));

byte[] deMsg = rsa.decryp(enMsg);

System.out.println("解密后是：" + new String(deMsg));

 

}

 

}

 

输出：

原文是：java安全编程——RSA

加密后是：_c_3乿e3岥赾悤_�_Q敊怦i�_f�儠B橱狎�_駸1=脖X揖�_p�!\x7BJ�_�-nZ臑�摁_UB厕瓀犆}~S_宜腒馾�=_

解密后是：java安全编程——RSA