3、AES加密算法

AES加密算法是密码学中的高级加密标准，该加密算法采用对称分组密码体制，密钥长度的最少支持为128、192、256，分组长度128位，算法应易于各种硬件和软件实现。这种加密算法是美国联邦政府采用的区块加密标准，这个标准用来替代原先的DES，已经被多方分析且广为全世界所使用。

过多原理不做解释，可以参考（AES加密算法原理http://www.jiamisoft.com/blog/858-aesjiamisuanfa.html）

java中的具体使用如下：

public class SecurityAESUtils {    private static Logger logger = LogManager.getLogger(SecurityAESUtils.class);    private static final String ENCODEING = "UTF-8";    private static final String ALGORITHM = "AES";//加密算法    private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//算法/工作模式/填充方式     /**     * 加密     * @param plaintext 明文     * @param secureKey 16位长度的密钥     * @return     */    public static String encrypt(String plaintext, String secureKey) throws Exception{        SecretKeySpec sks = getSecretKeySpec(secureKey);        Cipher encryptCipher = getCipher(Cipher.ENCRYPT_MODE, sks);        byte[] result = encryptCipher.doFinal(plaintext.getBytes(ENCODEING));        return  Base64.encodeBase64String(result);    }    /**     * 加密     * @param bytes      * @param secureKey 16位长度的密钥     * @return     */    public static String encryptBytes(byte[] bytes, String secureKey) throws Exception{        SecretKeySpec sks = getSecretKeySpec(secureKey);        Cipher encryptCipher = getCipher(Cipher.ENCRYPT_MODE, sks);        byte[] result = encryptCipher.doFinal(bytes);        return  Base64.encodeBase64String(result);    }    /**     * 解密     * @param ciphertext 密文     * @return secureKey 16位长度的密钥     * @throws Exception     */    public static String decrypt(String ciphertext, String secureKey) throws Exception {        SecretKeySpec sks = getSecretKeySpec(secureKey);        Cipher decryptCiphe = getCipher(Cipher.DECRYPT_MODE, sks);//initDecryptCipher(secureKey);        byte[] result =  decryptCiphe.doFinal(Base64.decodeBase64(ciphertext));        return new String(result, ENCODEING);    }    private static Cipher getCipher(int cipherMode, SecretKeySpec sks) throws Exception{        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);        cipher.init(cipherMode, sks);        return cipher;    }    private static SecretKeySpec getSecretKeySpec(String secureKey) throws Exception{        if(secureKey == null || secureKey.trim().equals("") || secureKey.length() != 16){            throw new Exception("密钥不能为空或密钥长度不对");        }        byte[] raw = secureKey.getBytes(ENCODEING);        SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM);        return skeySpec;    }    /**     * @Comment 加密不限制密码长度     * @Author Ron     * @Date 2017年9月12日 下午3:21:59     * @return     */    public static String encryptNotLimit(String plaintext, String secureKey) throws Exception{        SecretKeySpec sks = getSecretKeySpecByRandomSeed(secureKey);        Cipher encryptCipher = getCipher(Cipher.ENCRYPT_MODE, sks);        byte[] result = encryptCipher.doFinal(plaintext.getBytes(ENCODEING));        return Hex.encodeHexString(result);    }    /**     * @Comment 解密不限制密码长度     * @Author Ron     * @Date 2017年9月12日 下午3:22:30     * @return     */    public static String decryptNotLimit(String ciphertext, String secureKey) throws Exception {        SecretKeySpec sks = getSecretKeySpecByRandomSeed(secureKey);        Cipher decryptCiphe = getCipher(Cipher.DECRYPT_MODE, sks);        byte[] result =  decryptCiphe.doFinal(Hex.decodeHex(ciphertext.toCharArray()));        return new String(result, ENCODEING);    }    /**     * @Comment 构造私钥     * @Author Ron     * @Date 2017年9月12日 下午3:22:59     * @return     */    private static SecretKeySpec getSecretKeySpecByRandomSeed(String secureKey){        SecretKeySpec sks = null;        try {            KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM);            //安全随机数生成器             SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");//使用默认的SHA1PRNG算法            secureRandom.setSeed(secureKey.getBytes(ENCODEING));            kgen.init(128, secureRandom);             SecretKey secretKey = kgen.generateKey();            byte[] secretKeyEncoded = secretKey.getEncoded();            sks = new SecretKeySpec(secretKeyEncoded, ALGORITHM);        } catch (Exception e) {            logger.error("",e);        }        return sks;    }    public static void main(String[] args) throws Exception {        String key = "ron.zheng@tfscha";        String src = "我是Ron";        String enString = encrypt(src,key);        System.out.println("加密后的数据："+enString);        System.out.println("解密后的数据："+decrypt(enString,key));        //不限制密钥长度        String nkey = "[e-mail]";        enString = encryptNotLimit(src, nkey);        System.out.println("加密后的数据："+enString);        System.out.println("解密后的数据："+decryptNotLimit(enString,nkey));    }}