BASE64,MD5,SHA,HMAC加密與解密算法(java)

package com.ice.webos.util.security;

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.Key;
import java.security.MessageDigest;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
* <ul>
* <li>BASE64的加密解密是双向的，可以求反解。</li>
* <li>MD5、SHA以及HMAC是单向加密，任何数据加密后只会产生唯一的一个加密串，通常用来校验数据在传输过程中是否被修改。</li>
* <li>HMAC算法有一个密钥，增强了数据传输过程中的安全性，强化了算法外的不可控因素。</li>
* <li>DES DES-Data Encryption Standard,即数据加密算法。
* DES算法的入口参数有三个:Key、Data、Mode。
* <ul>
* <li>Key:8个字节共64位,是DES算法的工作密钥;</li>
* <li>Data:8个字节64位,是要被加密或被解密的数据;</li>
* <li>Mode:DES的工作方式,有两种:加密或解密。</li>
* </ul>
* </li>
* <ul>
* 
* @author Ice_Liu
* 
*/
public class CryptUtil {
private static final String KEY_MD5 = "MD5";
private static final String KEY_SHA = "SHA";
/**
* MAC算法可选以下多种算法
* 
* <pre>
* 
* HmacMD5 
* HmacSHA1 
* HmacSHA256 
* HmacSHA384 
* HmacSHA512 
* </pre>
*/
public static final String KEY_MAC = "HmacMD5";

/**
* BASE64解密
* 
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}

/**
* BASE64 加密
* 
* @param key
* @return
* @throws Exception
*/
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}

/**
* MD5加密
* 
* @param data
* @return
* @throws Exception
*/
public static byte[] encryptMD5(byte[] data) throws Exception {

MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);
md5.update(data);

return md5.digest();

}

/**
* SHA加密
* 
* @param data
* @return
* @throws Exception
*/
public static byte[] encryptSHA(byte[] data) throws Exception {

MessageDigest sha = MessageDigest.getInstance(KEY_SHA);
sha.update(data);

return sha.digest();

}

/**
* 初始化HMAC密钥
* 
* @return
* @throws Exception
*/
public static String initMacKey() throws Exception {
KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);
SecretKey secretKey = keyGenerator.generateKey();
return encryptBASE64(secretKey.getEncoded());
}

/**
* HMAC 加密
* 
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encryptHMAC(byte[] data, String key) throws Exception {
SecretKey secretKey = new SecretKeySpec(decryptBASE64(key), KEY_MAC);
Mac mac = Mac.getInstance(secretKey.getAlgorithm());
mac.init(secretKey);
return mac.doFinal(data);
}

/**
* DES 算法 <br>
* 可替换为以下任意一种算法，同时key值的size相应改变。
* 
* <pre>
* DES key size must be equal to 56 
* DESede(TripleDES) key size must be equal to 112 or 168 
* AES key size must be equal to 128, 192 or 256,but 192 and 256 bits may not be available 
* Blowfish key size must be multiple of 8, and can only range from 32 to 448 (inclusive) 
* RC2 key size must be between 40 and 1024 bits 
* RC4(ARCFOUR) key size must be between 40 and 1024 bits 
* </pre>
*/
public static final String ALGORITHM = "DES";

/**
* DES 算法转换密钥<br>
* 
* @param key
* @return
* @throws Exception
*/
private static Key toKey(byte[] key) throws Exception {
SecretKey secretKey = null;
if (ALGORITHM.equals("DES") || ALGORITHM.equals("DESede")) {
DESKeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
secretKey = keyFactory.generateSecret(dks);
} else {
// 当使用其他对称加密算法时，如AES、Blowfish等算法时，用下述代码替换上述三行代码
secretKey = new SecretKeySpec(key, ALGORITHM);
}
return secretKey;
}

/**
* DES 算法解密
* 
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decrypt(byte[] data, String key) throws Exception {
Key k = toKey(decryptBASE64(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, k);
return cipher.doFinal(data);
}

/**
* DES 算法加密
* 
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encrypt(byte[] data, String key) throws Exception {
Key k = toKey(decryptBASE64(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, k);
return cipher.doFinal(data);
}

/**
* DES 算法生成密钥
* 
* @return
* @throws Exception
*/
public static String initKey() throws Exception {
return initKey(null);
}

/**
* DES 算法生成密钥
* 
* @param seed
* @return
* @throws Exception
*/
public static String initKey(String seed) throws Exception {
SecureRandom secureRandom = null;
if (seed != null) {
secureRandom = new SecureRandom(decryptBASE64(seed));
} else {
secureRandom = new SecureRandom();
}
KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM);
kg.init(secureRandom);
SecretKey secretKey = kg.generateKey();
return encryptBASE64(secretKey.getEncoded());
}

public static void main(String[] args) {
try {
String s = "阿伯才的覆盖";
String b = CryptUtil.encryptBASE64(s.getBytes("UTF-8"));
System.out.println("BASE64加密后:" + b);
byte[] c = CryptUtil.decryptBASE64(b);
System.out.println("BASE64解密后:" + new String(c, "UTF-8"));

c = encryptMD5(s.getBytes());
System.out.println("MD5 加密后:" + new BigInteger(c).toString(16));

c = encryptSHA(s.getBytes());
System.out.println("SHA 加密后:" + new BigInteger(c).toString(16));

String key = initMacKey();
System.out.println("HMAC密匙:" + key);
c = encryptHMAC(s.getBytes(), key);
System.out.println("HMAC 加密后:" + new BigInteger(c).toString(16));

key = initKey();
System.out.println(ALGORITHM + "密钥:\t" + key);
c = encrypt(s.getBytes("UTF-8"), key);
System.out.println(ALGORITHM + " 加密后:" + new BigInteger(c).toString(16));
c = decrypt(c, key);
System.out.println(ALGORITHM + " 解密后:" + new String(c, "UTF-8"));
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}