密码学-AES加密解密-Java语言实现

文章目录

    • 什么是AES加密算法
    • java语言实现代码
    • 参考博客

什么是AES加密算法

AES是对称加密算法,也就是通信双方使用同一个密钥K。
A和B先沟通密钥K,然后A使用K对明文加密,生成密文H,将密文发给B,B收到密文后用密钥K解密。

java语言实现代码

package AES;

import java.nio.charset.Charset;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Scanner;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;



/**
 * @author qingnianren
 */
public class AES{
 
    /**
     * 生成密钥
     *
     * @return
     * @throws NoSuchAlgorithmException
     */
    public static SecretKey generateKey() throws NoSuchAlgorithmException {
    	//自动生成密钥
    	//实例化支持AES算法的密钥生成器(算法名称命名需按规定,否则抛出异常) 
        KeyGenerator secretGenerator = KeyGenerator.getInstance("AES");
        SecureRandom secureRandom = new SecureRandom();
        secretGenerator.init(secureRandom);
        //生成密钥
        SecretKey secretKey = secretGenerator.generateKey();
        //generateKey()方法返回自动生成的密钥值
        return secretKey;
    }
 
    static Charset charset = Charset.forName("UTF-8");
 
    /**
     * 加密
     *
     * @param content
     * @param secretKey
     * @return
     */
    public static byte[] encrypt(String content, SecretKey secretKey) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException { // 加密
        return aes(content.getBytes(charset), Cipher.ENCRYPT_MODE, secretKey);
    }
 
    /**
     * 解密
     *
     * @param contentArray
     * @param secretKey
     * @return
     */
    public static String decrypt(byte[] contentArray, SecretKey secretKey) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException { // 解密
        byte[] result = aes(contentArray, Cipher.DECRYPT_MODE, secretKey);
        return new String(result, charset);
    }
 
    private static byte[] aes(byte[] contentArray, int mode, SecretKey secretKey)
            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(mode, secretKey);
        byte[] result = cipher.doFinal(contentArray);
        return result;
    }
 
    public static void main(String[] args) {
        System.out.println("请输入要加密的明文:");
        //从键盘读入要加密的明文
        Scanner in =new Scanner(System.in);
        String content=in.nextLine();
        SecretKey secretKey;
        try {
            long timeStartEncry = System.currentTimeMillis();
            // 生成密钥,调用自动生成密钥的函数
            secretKey = generateKey();
 
            byte[] encryptResult = encrypt(content, secretKey);
            long timeEndEncry = System.currentTimeMillis();
            System.out.println("加密后的结果为==" + new String(encryptResult, charset));
 
            String decryptResult = decrypt(encryptResult, secretKey);
            System.out.println("解密后的结果==" + decryptResult);
 
            System.out.println("加密用时:" + (timeEndEncry - timeStartEncry));
        } catch (NoSuchAlgorithmException | InvalidKeyException | NoSuchPaddingException | IllegalBlockSizeException | BadPaddingException e) {
            e.printStackTrace();
        }
    }
}

运行结果·:
密码学-AES加密解密-Java语言实现_第1张图片

参考博客

java实现AES加解密
java实现DES加解密算法–从文件中读取

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