aes.java.svn-base

多线程加密聊天室,支持多线程客户端链接服务器端

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package mytools;

import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;

/**
 *
 * @author DJ尐舞
 */
public class AES {

    private Cipher cipher;
    private byte[] key;
    SecretKeySpec skeySpec;
    /**
     * 对AES算法构造函数
     */
    public AES() {
        init();
    }
    /**
     * 初始化AES加密对象
     */
    public void init() {
        this.key = AES.getKey();
        skeySpec = new SecretKeySpec(key, "AES");
        try {
            cipher = Cipher.getInstance("AES");
        } catch (NoSuchAlgorithmException ex) {
            System.out.println("初始化AES失败：本机上找不到算法AES");
        } catch (NoSuchPaddingException ex) {
            System.out.println("初始化AES失败");
        }
    }

    /**
     * 对数据用AES算法加密
     * @param plainText  要加密的字节数组
     * @param key  密钥
     * @return 加密后的字节数组
     */
    public byte[] encrypt(byte[] plainText) {
        try {
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
            byte[] decryptText = cipher.doFinal(plainText);
            return decryptText;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 对AES算法加密的数据解密
     * @param cipherText  要解密的字节数组
     * @param key  密钥
     * @return 解密后的字节数组
     */
    public byte[] decrypt(byte[] cipherText) throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException {

            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] plainText = cipher.doFinal(cipherText);
            return plainText;

    }
    /**
     * 从客户端目录下查找文件skey.dat，从中读取密钥
     * @return 返回密钥的字节数组
     */
    public static byte[] getKey() {
        java.io.FileInputStream in = null;
        byte[] key = new byte[16];
        try {
            in = new java.io.FileInputStream("skey.dat");
            in.read(key);
            in.close();
        } catch (IOException ex) {
            System.out.println("密钥读出失败");
        }
//         finally {
//            try {
//                in.close();
//            } catch (IOException ex) {
//                System.out.println("文件关闭失败");
//            }
//        }
        return key;
    }

    /**
     * 生成密钥
     * @throws java.security.NoSuchAlgorithmException 找不到AES算法
     */
    public static void generateKey() throws NoSuchAlgorithmException {
        //产生密钥
        java.io.FileOutputStream out = null;
        try {
            KeyGenerator kgen;
            kgen = KeyGenerator.getInstance("AES");
            kgen.init(128);
            SecretKey skey = kgen.generateKey();
            out = new java.io.FileOutputStream("skey.dat");
            out.write(skey.getEncoded());
            out.close();
            System.out.println("创建密钥成功");
        } catch (IOException ex) {
            System.out.println("密钥写入文件失败");
        } finally {
            try {
                out.close();
            } catch (IOException ex) {
                System.out.println("文件关闭失败");
            }
        }
    }
}