Crypto.java

package com.liuxey.uitl;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.security.SecureRandom;

/**
 * <p>加密工具类
 *
 * @author Liuxey
 * @date 2014年1月14日
 */
public class Crypto {

    // AES
    /**
     * <p>
     * // Description AES 加密
     *
     * @param content 加密内容
     * @param salt 加密密钥
     * @param encoding 编码, 如：UTF-8
     *
     * @return 加密串
     */
    public static String AESEncrypt(String content, String salt, String encoding) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(salt.getBytes());
            kgen.init(128, secureRandom);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES"); // 创建密码器
            byte[] byteContent = content.getBytes(encoding);
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);

            return parseByte2HexStr(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * <p>
     * // Description AES 解密
     *
     * @param code 加密串
     * @param salt 加密密钥
     * @param encoding 编码, 如：UTF-8
     *
     * @return 原始内容
     */
    public static String AESDecrypt(String code, String salt, String encoding) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(salt.getBytes());
            kgen.init(128, secureRandom);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES"); // 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(parseHexStr2Byte(code));
            return new String(result, encoding);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * <p>
     * // Description AES 加密
     *
     * @param content 加密内容
     * @param salt 加密密钥
     *
     * @return 加密串
     */
    public static String AESEncrypt(String content, String salt) {
        return AESEncrypt(content, salt, Constant.ENCODING);
    }

    /**
     * <p>
     * // Description AES 解密
     *
     * @param code 加密串
     * @param salt 加密密钥
     *
     * @return 原始内容
     */
    public static String AESDecrypt(String code, String salt) {
        return AESDecrypt(code, salt, Constant.ENCODING);
    }

    /**
     * 将二进制转换成16进制
     *
     * @param buf
     * @return
     */
    private static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     *
     * @param hexStr
     * @return
     */
    private static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
                    16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    /**
     * 计算MD5值
     *
     * @param bytes
     * @return
     */
    public final static String md5(byte[] bytes) {
        try {
            char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                    'a', 'b', 'c', 'd', 'e', 'f' };
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(bytes);
            byte[] md = mdTemp.digest();
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * <p> MD5 加密
     *
     * @param content 加密内容
     * @param encoding 编码, 如：UTF-8
     *
     * @return 加密串
     */
    public final static String md5(String content, String encoding) {
        try {
            byte[] strTemp = content.getBytes(encoding);
            return md5(strTemp);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * <p> MD5 加密
     *
     * @param content 加密内容
     *
     * @return 加密串
     */
    public final static String md5(String content) {
        return md5(content, Constant.ENCODING);
    }

    /**
     * 加盐 MD5 加密
     * @param content
     * @return
     */
    public final static String md5WithSalt(String content, String salt) {
        return md5WithSalt(content, salt, Constant.ENCODING);
    }

    /**
     * 加盐 MD5 加密
     *
     * @param content
     * @param salt
     * @param encoding
     * @return
     */
    public final static String md5WithSalt(String content, String salt, String encoding) {
        return md5(content + "#" + salt, encoding);
    }

    /**
     * <p> URL编码
     *
     * @param content 编码内容
     * @param encode 编码
     * @return
     */
    public final static String urlEncode(String content, String encode) {
        if (content != null && !content.equals("")) {
            try {
                String result = URLEncoder.encode(content, encode);
                return result;

            } catch (UnsupportedEncodingException e) {
                return "";
            }

        }else {
            return "";
        }
    }

    /**
     * <p> URL解码
     *
     * @param content 编码内容
     * @param encode 编码
     * @return
     */
    public final static String urlDecode(String content, String encode) {
        if (content != null && !content.equals("")) {
            try {
                String result = URLDecoder.decode(content, encode);
                return result;

            } catch (UnsupportedEncodingException e) {
                return "";
            }

        }else {
            return "";
        }
    }

}