AESUtils.java

package com.xiaomai.geek.common.utils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * Created by XiaoMai on 2017/4/19.
 */

public class AESUtils {
    private final static String HEX = "0123456789ABCDEF";

    public static String encrypt(String content) throws Exception {
        return encrypt("F9873622AF42269D252C789D7CDD5D7FD6912F40", content);
    }

    public static String decrypt(String content) throws Exception {
        return decrypt("F9873622AF42269D252C789D7CDD5D7FD6912F40", content);
    }

    public static String encrypt(String seed, String cleartext) throws Exception {
        byte[] rawKey = deriveKeyInsecurely(seed, 32).getEncoded();
        byte[] result = encrypt(rawKey, cleartext.getBytes());
        return toHex(result);
    }

    public static String decrypt(String seed, String encrypted) throws Exception {
        byte[] rawKey = deriveKeyInsecurely(seed, 32).getEncoded();
        byte[] enc = toByte(encrypted);
        byte[] result = decrypt(rawKey, enc);
        return new String(result);
    }

    private static SecretKey deriveKeyInsecurely(String password, int
            keySizeInBytes) {
        byte[] passwordBytes = password.getBytes();
        return new SecretKeySpec(
                InsecureSHA1PRNGKeyDerivator.deriveInsecureKey(
                        passwordBytes, keySizeInBytes),
                "AES");
    }

    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, new IvParameterSpec(new byte[cipher.getBlockSize()]));
        return cipher.doFinal(clear);
    }

    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, new IvParameterSpec(new byte[cipher.getBlockSize()]));
        return cipher.doFinal(encrypted);
    }

    private static String toHex(String txt) {
        return toHex(txt.getBytes());
    }

    private static String fromHex(String hex) {
        return new String(toByte(hex));
    }

    private 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;
    }

    private 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 static void appendHex(StringBuffer sb, byte b) {
        sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
    }
}