Java 加解密技术系列之 HMAC

import com.google.common.base.Strings;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;

import javax.crypto.KeyGenerator;

import javax.crypto.Mac;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import java.security.NoSuchAlgorithmException;

/**

* Created by xiang.li on 2015/2/27.

*/

public class HMAC {

/**

* 定义加密方式

* MAC算法可选以下多种算法

* <pre>

* HmacMD5

* HmacSHA1

* HmacSHA256

* HmacSHA384

* HmacSHA512

* </pre>

*/

private final static String KEY_MAC = "HmacMD5";

/**

* 全局数组

*/

private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",

"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

/**

* 构造函数

*/

public HMAC() {

}

/**

* BASE64 加密

* @param key 需要加密的字节数组

* @return 字符串

* @throws Exception

*/

public static String encryptBase64(byte[] key) throws Exception {

return (new BASE64Encoder()).encodeBuffer(key);

}

/**

* BASE64 解密

* @param key 需要解密的字符串

* @return 字节数组

* @throws Exception

*/

public static byte[] decryptBase64(String key) throws Exception {

return (new BASE64Decoder()).decodeBuffer(key);

}

/**

* 初始化HMAC密钥

* @return

*/

public static String init() {

SecretKey key;

String str = "";

try {

KeyGenerator generator = KeyGenerator.getInstance(KEY_MAC);

key = generator.generateKey();

str = encryptBase64(key.getEncoded());

} catch (NoSuchAlgorithmException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}

return str;

}

/**

* HMAC加密

* @param data 需要加密的字节数组

* @param key 密钥

* @return 字节数组

*/

public static byte[] encryptHMAC(byte[] data, String key) {

SecretKey secretKey;

byte[] bytes = null;

try {

secretKey = new SecretKeySpec(decryptBase64(key), KEY_MAC);

Mac mac = Mac.getInstance(secretKey.getAlgorithm());

mac.init(secretKey);

bytes = mac.doFinal(data);

} catch (Exception e) {

e.printStackTrace();

}

return bytes;

}

/**

* HMAC加密

* @param data 需要加密的字符串

* @param key 密钥

* @return 字符串

*/

public static String encryptHMAC(String data, String key) {

if (Strings.isNullOrEmpty(data)) {

return null;

}

byte[] bytes = encryptHMAC(data.getBytes(), key);

return byteArrayToHexString(bytes);

}

/**

* 将一个字节转化成十六进制形式的字符串

* @param b 字节数组

* @return 字符串

*/

private static String byteToHexString(byte b) {

int ret = b;

//System.out.println("ret = " + ret);

if (ret < 0) {

ret += 256;

}

int m = ret / 16;

int n = ret % 16;

return hexDigits[m] + hexDigits
;

}

/**

* 转换字节数组为十六进制字符串

* @param bytes 字节数组

* @return 十六进制字符串

*/

private static String byteArrayToHexString(byte[] bytes) {

StringBuffer sb = new StringBuffer();

for (int i = 0; i < bytes.length; i++) {

sb.append(byteToHexString(bytes[i]));

}

return sb.toString();

}

/**

* 测试方法

* @param args

*/

public static void main(String[] args) throws Exception {

String key = HMAC.init();

System.out.println("Mac密钥:\n" + key);

String word = "123";

System.out.println(encryptHMAC(word, key));

}