DataCipher.java

/*******************************************************************************
 * Copyright [2015] [Onboard team of SERC, Peking University]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.onboard.utils;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * 通过DES加密解密实现一个String字符串的加密和解密.
 * 
 * @author gourui
 * 
 */
public class DataCipher {

    private static String privateKey = "adasdasdad";

    public static String encode(String str) {
        String result = null;
        try {
            result = byteArrayToHexString(encrypt(str.getBytes()));
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return result;
    }

    public static String decode(String str) {
        String result = null;
        try {
            result = new String((decrypt(hexStringToByteArray(str))));
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return result;
    }

    private static byte[] getRawKeyData() {
        return privateKey.getBytes();
    }

    /**
     * 加密方法
     * 
     */
    private static byte[] encrypt(byte[] data) throws InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException,
            NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
        // DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密匙数据创建一个DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(getRawKeyData());
        // 创建一个密匙工厂，然后用它把DESKeySpec转换成一个SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey key = keyFactory.generateSecret(dks);
        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance("DES");
        // 用密匙初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, key, sr);
        // 正式执行加密操作
        byte[] encryptedData = cipher.doFinal(data);

        return encryptedData;
    }

    /**
     * 解密方法
     * 
     */
    private static byte[] decrypt(byte[] encryptedData) throws IllegalBlockSizeException, BadPaddingException,
            InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeySpecException {
        // DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密匙数据创建一个DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(getRawKeyData());
        // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成一个SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey key = keyFactory.generateSecret(dks);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance("DES");
        // 用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, key, sr);
        // 正式执行解密操作
        byte decryptedData[] = cipher.doFinal(encryptedData);
        return decryptedData;
    }

    private static String byteArrayToHexString(byte[] b) {
        StringBuffer sb = new StringBuffer(b.length * 2);
        for (int i = 0; i < b.length; i++) {
            int v = b[i] & 0xff;
            if (v < 16) {
                sb.append('0');
            }
            sb.append(Integer.toHexString(v));
        }
        return sb.toString().toLowerCase();
    }

    private static byte[] hexStringToByteArray(String s) {
        byte[] b = new byte[s.length() / 2];
        for (int i = 0; i < b.length; i++) {
            int index = i * 2;
            int v = Integer.parseInt(s.substring(index, index + 2), 16);
            b[i] = (byte) v;
        }
        return b;
    }
}