HMAC
HMAC(Hash Message Authentication Code,散列消息鉴别码,基于密钥的Hash算法的认证协议。消息鉴别码实现鉴别的原理是,用公开函数和密钥产生一个固定长度的值作为认证标识,用这个标识鉴别消息的完整性。使用一个密钥生成一个固定大小的小数据块,即MAC,并将其加入到消息中,然后传输。接收方利用与发送方共享的密钥进行鉴别认证等。
BASE64的加密解密是双向的,可以求反解。
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。其中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。
单向加密的用途主要是为了校验数据在传输过程中是否被修改。
代码如下:
import java.math.BigInteger; import java.security.InvalidKeyException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import javax.crypto.KeyGenerator; import javax.crypto.Mac; import javax.crypto.SecretKey; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.Base64; public class MyEncrypt { public static final String KEY_SHA = "SHA"; public static final String KEY_MD5 = "MD5"; public static final String KEY_MAC = "HmacMD5"; // sun不推荐使用它们自己的base64,用apache的挺好 /** * BASE64解密 */ public static byte[] decryptBASE64(byte[] dest) { if (dest == null) { return null; } return Base64.decodeBase64(dest); } /** * BASE64加密 */ public static byte[] encryptBASE64(byte[] origin) { if (origin == null) { return null; } return Base64.encodeBase64(origin); } /** * MD5加密 * * @throws NoSuchAlgorithmException */ public static byte[] encryptMD5(byte[] data) throws NoSuchAlgorithmException { if (data == null) { return null; } MessageDigest md5 = MessageDigest.getInstance(KEY_MD5); md5.update(data); return md5.digest(); } /** * SHA加密 * * @throws NoSuchAlgorithmException */ public static byte[] encryptSHA(byte[] data) throws NoSuchAlgorithmException { if (data == null) { return null; } MessageDigest sha = MessageDigest.getInstance(KEY_SHA); sha.update(data); return sha.digest(); } /** * 初始化HMAC密钥 * * @throws NoSuchAlgorithmException */ public static String initMacKey() throws NoSuchAlgorithmException { KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC); SecretKey secretKey = keyGenerator.generateKey(); return new String(encryptBASE64(secretKey.getEncoded())); } /** * HMAC加密 * * @throws NoSuchAlgorithmException * @throws InvalidKeyException */ public static byte[] encryptHMAC(byte[] data, String key) throws NoSuchAlgorithmException, InvalidKeyException { SecretKey secretKey = new SecretKeySpec(decryptBASE64(key.getBytes()), KEY_MAC); Mac mac = Mac.getInstance(secretKey.getAlgorithm()); mac.init(secretKey); return mac.doFinal(data); } public static void main(String[] args) throws Exception { // TODO Auto-generated method stub String data = "简单加密"; System.out.println(new BigInteger(encryptBASE64(data.getBytes())).toString(16)); System.out.println(new BigInteger(encryptBASE64(data.getBytes())).toString(32)); System.out.println(new String(decryptBASE64(encryptBASE64(data.getBytes())))); System.out.println(new BigInteger(encryptMD5(data.getBytes())).toString()); System.out.println(new BigInteger(encryptSHA(data.getBytes())).toString()); System.out.println(new BigInteger(encryptHMAC(data.getBytes(), initMacKey())).toString()); } } |
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