AES加密技术

public class SimpleCrypto {  

    public static String encrypt(String seed, String cleartext) throws Exception {  

        byte[] rawKey = getRawKey(seed.getBytes());  

        byte[] result = encrypt(rawKey, cleartext.getBytes());  

        return toHex(result);  

    }  

    public static String decrypt(String seed, String encrypted) throws Exception {  

        byte[] rawKey = getRawKey(seed.getBytes());  

        byte[] enc = toByte(encrypted);  

        byte[] result = decrypt(rawKey, enc);  

        return new String(result);  

    }  

   

    private static byte[] getRawKey(byte[] seed) throws Exception {  

        KeyGenerator kgen = KeyGenerator.getInstance("AES");  

        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");  

        sr.setSeed(seed);  

        kgen.init(128, sr); // 192 and 256 bits may not be available  

        SecretKey skey = kgen.generateKey();  

        byte[] raw = skey.getEncoded();  

        return raw;  

    }  

    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {  

        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");  

        Cipher cipher = Cipher.getInstance("AES");  

        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);  

        byte[] encrypted = cipher.doFinal(clear);  

        return encrypted;  

    }  

    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {  

        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");  

        Cipher cipher = Cipher.getInstance("AES");  

        cipher.init(Cipher.DECRYPT_MODE, skeySpec);  

        byte[] decrypted = cipher.doFinal(encrypted);  

        return decrypted;  

    }  

    public static String toHex(String txt) {  

        return toHex(txt.getBytes());  

    }  

    public static String fromHex(String hex) {  

        return new String(toByte(hex));  

    }  

        

    public static byte[] toByte(String hexString) {  

        int len = hexString.length()/2;  

        byte[] result = new byte[len];  

        for (int i = 0; i < len; i++)  

            result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();  

        return result;  

    }  

    public static String toHex(byte[] buf) {  

        if (buf == null)  

            return "";  

        StringBuffer result = new StringBuffer(2*buf.length);  

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

            appendHex(result, buf[i]);  

        }  

        return result.toString();  

    }  

    private final static String HEX = "0123456789ABCDEF";  

    private static void appendHex(StringBuffer sb, byte b) {  

        sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));  

    }  

   public static void main(String[] args) {
	   try {
		   //加密
		String encryptingCode = SimpleCrypto.encrypt("123","456");
		System.out.println(encryptingCode);
		//解密
		String originalText = SimpleCrypto.decrypt("123", encryptingCode);
		System.out.println(originalText);
	} catch (Exception e) {
		e.printStackTrace();
	}

 }
}