利用AES加密解密（Java&跨平臺）

時間 2019-11-12

原文原文鏈接

配置文件中保存明文密碼顯得不那麼安全，這裏解決這個問題。配置文件中保存加密後的密文，在使用的時候再解密還原。java

java.util.Base64是Java 1.8新增的，若是jdk版本低於1.8，請更換成其餘的Base64工具。安全

import java.io.UnsupportedEncodingException;
  import java.security.InvalidKeyException;
  import java.security.NoSuchAlgorithmException;
  import java.security.SecureRandom;
  import java.util.Base64;

  import javax.crypto.BadPaddingException;
  import javax.crypto.Cipher;
  import javax.crypto.IllegalBlockSizeException;
  import javax.crypto.KeyGenerator;
  import javax.crypto.NoSuchPaddingException;
  import javax.crypto.spec.SecretKeySpec;

  public class EncryptUtils {

  	/**
  	 * AES加密
  	 * 
  	 * [@param](https://my.oschina.net/u/2303379) ciphertext
  	 *            待加密的內容
  	 * [@param](https://my.oschina.net/u/2303379) encryptKey
  	 *            加密密鑰
  	 * [@return](https://my.oschina.net/u/556800) 加密後的byte[]
  	 */
  	public static byte[] aesEncryptToBytes(String ciphertext, String encryptKey) {
  		try {
  			return getCipher(Cipher.ENCRYPT_MODE, encryptKey).doFinal(
  					ciphertext.getBytes("utf-8"));
  		} catch (IllegalBlockSizeException e) {
  			e.printStackTrace();
  			return null;
  		} catch (BadPaddingException e) {
  			e.printStackTrace();
  			return null;
  		} catch (UnsupportedEncodingException e) {
  			e.printStackTrace();
  			return null;
  		} catch (NoSuchAlgorithmException e) {
  			e.printStackTrace();
  			return null;
  		}
  	}

  	/**
  	 * AES解密
  	 * 
  	 * [@param](https://my.oschina.net/u/2303379) encryptBytes
  	 *            待解密的byte[]
  	 * [@param](https://my.oschina.net/u/2303379) decryptKey
  	 *            解密密鑰
  	 * @return 解密後的String
  	 */
  	public static String aesDecryptByBytes(byte[] encryptBytes,
  			String decryptKey) {
  		byte[] decryptBytes;
  		try {
  			decryptBytes = getCipher(Cipher.DECRYPT_MODE, decryptKey).doFinal(
  					encryptBytes);
  		} catch (IllegalBlockSizeException e) {
  			e.printStackTrace();
  			return null;
  		} catch (BadPaddingException e) {
  			e.printStackTrace();
  			return null;
  		} catch (NoSuchAlgorithmException e) {
  			e.printStackTrace();
  			return null;
  		}

  		return new String(decryptBytes);
  	}

  	private static Cipher getCipher(int cipherMode, String encryptKey) throws NoSuchAlgorithmException {
  		KeyGenerator kgen;
  		SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
  		random.setSeed(encryptKey.getBytes());
  		try {
  			kgen = KeyGenerator.getInstance("AES");
  		} catch (NoSuchAlgorithmException e) {
  			e.printStackTrace();
  			return null;
  		}
  		kgen.init(128, random);
  		Cipher cipher;
  		try {
  			cipher = Cipher.getInstance("AES");
  		} catch (NoSuchAlgorithmException e) {
  			e.printStackTrace();
  			return null;
  		} catch (NoSuchPaddingException e) {
  			e.printStackTrace();
  			return null;
  		}
  		try {
  			cipher.init(cipherMode, new SecretKeySpec(kgen.generateKey()
  					.getEncoded(), "AES"));
  		} catch (InvalidKeyException e) {
  			e.printStackTrace();
  			return null;
  		}
  		return cipher;
  	}

  	/**
  	 * 根據傳入的內容和密鑰，返回加密後獲得的base64字符串
  	 * 
  	 * @author ChangJian
  	 * @data 2018年7月25日
  	 * @param ciphertext
  	 *            待加密的內容
  	 * @param encryptKey
  	 *            密鑰
  	 * @return
  	 */
  	public static String encryptAesBase64(String ciphertext, String encryptKey) {
  		return Base64.getEncoder().encodeToString(aesEncryptToBytes(ciphertext, encryptKey));
  	}

  	/**
  	 * 把encryptAesBase64方法生成的base64形式的密碼還原成明文密碼
  	 * 
  	 * @author ChangJian
  	 * @data 2018年7月25日
  	 * @param ciphertext
  	 *            base64形式的密碼
  	 * @param decryptKey
  	 *            解密的密鑰
  	 * @return
  	 */
  	public static String decryptAesBase64(String ciphertext, String decryptKey) {
  		return aesDecryptByBytes(Base64.getDecoder().decode(ciphertext), decryptKey);
  	}

  	/**
  	 * 測試
  	 */
  	public static void main(String[] args) {
  		String password = "password123456";
  		String decryptKey = "8F85C42859C4B883817EB72E37AF2A3E";
  		String ciphertext = encryptAesBase64(password, decryptKey);
  		System.out.println("密文：" + ciphertext);
  		System.out.println("解密：" + decryptAesBase64(ciphertext, decryptKey));
  	}
  }