Java加密解密工具類(使用自定義密文進行加密解密運算)記錄

private static final String AES = "AES";
    private static int keysizeAES = 128;
    private static String charset = "utf-8";

    /**
     * 使用AES加密算法經行加密（可逆）
     * @param res 需要加密的密文
     * @param key 秘鑰
     * @return
     */
    public static String AESencode(String res, String key) {
        return keyGeneratorES(res, AES, key, keysizeAES, true);
    }

    /**
     * 對使用AES加密算法的密文進行解密
     * @param res 需要解密的密文
     * @param key 秘鑰
     * @return
     */
    public static String AESdecode(String res, String key) {
        return keyGeneratorES(res, AES, key, keysizeAES, false);
    }

    /**
     * 使用KeyGenerator雙向加密，DES/AES，注意這裡轉化為字元串的時候是将2進制轉為16進制格式的字元串，不是直接轉，因為會出錯
     * @param res 加密的原文
     * @param algorithm 加密使用的算法名稱
     * @param key  加密的秘鑰
     * @param keysize
     * @param isEncode
     * @return
     */
    private static String keyGeneratorES(String res, String algorithm, String key, int keysize, boolean isEncode) {
        try {
            KeyGenerator kg = KeyGenerator.getInstance(algorithm);
            if (keysize == 0) {
                byte[] keyBytes = charset == null ? key.getBytes() : key.getBytes(charset);
                kg.init(new SecureRandom(keyBytes));
            } else if (key == null) {
                kg.init(keysize);
            } else {
                byte[] keyBytes = charset == null ? key.getBytes() : key.getBytes(charset);
                /**windows中使用
                    kg.init(keysize, new SecureRandom(keyBytes));
                */

                /**Linux中使用，此處經過實際生産測試可用*/
                SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
                random.setSeed(keyBytes);
                kg.init(keysize, random);
            }
            SecretKey sk = kg.generateKey();
            SecretKeySpec sks = new SecretKeySpec(sk.getEncoded(), algorithm);
            Cipher cipher = Cipher.getInstance(algorithm);
            if (isEncode) {
                cipher.init(Cipher.ENCRYPT_MODE, sks);
                byte[] resBytes = charset == null? res.getBytes() : res.getBytes(charset);
                return parseByte2HexStr(cipher.doFinal(resBytes));
            } else {
                cipher.init(Cipher.DECRYPT_MODE, sks);
                return new String(cipher.doFinal(parseHexStr2Byte(res)));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**将二進制轉換成16進制 */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**将16進制轉換為二進制*/
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static void main(String[] args) {
        System.out.println(AESencode("測試解密文字","hello"));
        System.out.println(AESdecode("130FB21FB4B85E0C60C2B995AC2A30","hello"));
    }