package com.qzd.hit.util;

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

public class Demo {

	/*** main
    * @author qizai
    * data: params
    * encStr: Here, the length of the key must be a multiple of 16
    */
	public static void main(String[] args) throws Exception {
		// Encrypt Data
        String key = "ROcb6JybnKILLOlO"; // Secret Key length must be (16 24 32)
		String data = "[\"123456789\"]"; // Content to be encrypted
		String encStr = encrypt(data, key);  // Content to be decrypted
		System.out.println(encStr); //Encrypted data: w6oijM0xddQrItnH3UybLQ==
		// Decrypt Data
		String decStr = decrypt(encStr, key);
		System.out.println(decStr); //Decrypted data: ["123456789"]
	}

	public static String encrypt(String content, String password) {
		if (StringUtils.isEmpty(content) || StringUtils.isEmpty(password)) {
			System.out.println("AES encryption params is null");
			return null;
		}
		try {
			// Create cipher
			Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
			byte[] byteContent = content.getBytes("UTF-8");
			// Initialize as cryptographic cipher
			cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(password));
			byte[] encryptByte = cipher.doFinal(byteContent);
			return org.apache.commons.codec.binary.Base64.encodeBase64String(encryptByte);
		} catch (Exception e) {
			System.out.println("AES encryption operation has exception,content:{},password:{}", content, password, e);
		}
		return null;
	}

	public static String decrypt(String encryptContent, String password) throws Exception {
		if (StringUtils.isEmpty(encryptContent) || StringUtils.isEmpty(password)) {
			System.out.println("AES The request parameter is null");
			return null;
		}
		Cipher cipher = null;
		cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
		// Set to decryption mode
		cipher.init(Cipher.DECRYPT_MODE, getSecretKey(password));
		// Perform decryption operation
		byte[] result = cipher.doFinal(org.apache.commons.codec.binary.Base64.decodeBase64(encryptContent));
		return new String(result, "UTF-8");
	}

	private static SecretKeySpec getSecretKey(final String password) throws NoSuchAlgorithmException {
		// Generates the generator for the specified algorithm key
		KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
		SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
		random.setSeed(password.getBytes());
		keyGenerator.init(128, random);
		// Grnerate Key
		SecretKey secretKey = keyGenerator.generateKey();
		// Key converted to AES
		return new SecretKeySpec(secretKey.getEncoded(), "AES");
	}
}