AES對稱加密

題記：項目中對於一些不太重要的功能點，可以使用對稱加密，但如果是針對用戶密碼之類的，請使用MD5等加密技術。

對稱加密：是指對字符串的加密和解密是同一個密鑰，因此是存在風險的，一旦拿到了你的密鑰，內容就完全暴露了哦。

AES代碼如下：

package com.test.shiro.config;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;

/**
 * AES-128-CBC加解密模式
 */
public class AES {

    /**
     * 加密
     *
     * @param encData   要加密的數據
     * @param secretKey 密鑰 ,16位的數字和字母
     * @param vector    初始化向量,16位的數字和字母
     * @return
     */
    public static String encrypt(String encData, String secretKey, String vector)
            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
            InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {

        if (secretKey == null) {
            return null;
        }
        byte[] raw = secretKey.getBytes();
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");// "算法/模式/補碼方式"
        IvParameterSpec iv = new IvParameterSpec(vector.getBytes());// 使用CBC模式，需要一個向量iv，可增加加密算法的強度
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
        byte[] encrypted = cipher.doFinal(encData.getBytes());
        Base64.Encoder encoder = Base64.getEncoder();
        return encoder.encodeToString(encrypted);

    }


    /**
     * 解密
     *
     * @param decData
     * @param secretKey 密鑰
     * @param vector    鹽
     * @return
     */
    public static String decrypt(String decData, String secretKey, String vector)
            throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException,
            InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {

        if (secretKey == null) {
            return null;
        }
        if (vector == null) {
            return null;
        }
        byte[] raw = secretKey.getBytes("ASCII");
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        IvParameterSpec iv = new IvParameterSpec(vector.getBytes());
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
        Base64.Decoder decoder = Base64.getDecoder();
        byte[] original = cipher.doFinal(decoder.decode(decData));
        String originalString = new String(original);
        return originalString;
    }

    /**
     * 使用指定的字符串生成秘鑰
     */
    public static String getKeyByPass(String password) {
        //生成秘鑰
        //String password="testkey00";
        try {
            KeyGenerator kg = KeyGenerator.getInstance("AES");
            // kg.init(128);//要生成多少位，只需要修改這里即可128, 192或256
            //SecureRandom是生成安全隨機數序列，password.getBytes()是種子，只要種子相同，序列就一樣，所以生成的秘鑰就一樣。
            kg.init(128, new SecureRandom(password.getBytes()));
            SecretKey sk = kg.generateKey();
            byte[] b = sk.getEncoded();
            String s = byteToHexString(b);
            return s;
        }
        catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            System.out.println("沒有此算法。");
        }
        return "";
    }
    public static byte[] generateDesKey(int length) throws Exception {
        //實例化
        KeyGenerator kgen = null;
        kgen = KeyGenerator.getInstance("AES");
        //設置密鑰長度
        kgen.init(length);
        //生成密鑰
        SecretKey skey = kgen.generateKey();
        //返回密鑰的二進制編碼
        return skey.getEncoded();
    }

    public static String byteToHexString(byte[] bytes) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) {
            String strHex = Integer.toHexString(bytes[i]);
            if (strHex.length() > 3) {
                sb.append(strHex.substring(6));
            } else {
                if (strHex.length() < 2) {
                    sb.append("0" + strHex);
                } else {
                    sb.append(strHex);
                }
            }
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        String initPsd = "werweferwer";
        String secretKey =getKeyByPass(initPsd);
        System.out.println(secretKey);
        String vector= "1234rt5t34tergy6";
        String encrptyData = "yangweref";
        try {
            String encryptPassword = encrypt(encrptyData, secretKey, vector);
            System.out.println(encryptPassword);
            String decrptyPassword = decrypt(encryptPassword,secretKey,vector);
            System.out.println(decrptyPassword);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

 

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