java AES对称加密工具类

旧城等待， 2023-08-17 16:33 160阅读 0赞

package com.util;
    
    import java.io.UnsupportedEncodingException;
    
    import javax.crypto.Cipher;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;
    
    import sun.misc.BASE64Decoder;
    import sun.misc.BASE64Encoder;
    
    /**
     * AES加密工具类
     * @author xWang
     * @Date 2019-08-27
     */
    public class AesEncodeUtil {
    
        //偏移量
        public static final String VIPARA = "1234567876543210";   //AES 为16bytes. DES 为8bytes
    
        //编码方式
        public static final String CODE_TYPE = "UTF-8";
        //public static final String CODE_TYPE = "GBK";
    
        //填充类型
        public static final String AES_TYPE = "AES/ECB/PKCS5Padding";
        //public static final String AES_TYPE = "AES/ECB/PKCS7Padding";
        //此类型 加密内容,密钥必须为16字节的倍数位,否则抛异常,需要字节补全再进行加密
        //public static final String AES_TYPE = "AES/ECB/NoPadding";
        //java 不支持ZeroPadding
        //public static final String AES_TYPE = "AES/CBC/ZeroPadding";
    
        //私钥
        private static final String AES_KEY="1111222233334444";   //AES固定格式为128/192/256 bits.即：16/24/32bytes。DES固定格式为128bits，即8bytes。
    
        //字符补全
        private static final String[] consult = new String[]{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G"};
    
    
        /**
         * 加密
         *
         * @param cleartext
         * @return
         */
        public static String encrypt(String cleartext) {
            //加密方式： AES128(CBC/PKCS5Padding) + Base64, 私钥：1111222233334444
            try {
                IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
                //两个参数，第一个为私钥字节数组， 第二个为加密方式 AES或者DES
                SecretKeySpec key = new SecretKeySpec(AES_KEY.getBytes(), "AES");
                //实例化加密类，参数为加密方式，要写全
                Cipher cipher = Cipher.getInstance(AES_TYPE); //PKCS5Padding比PKCS7Padding效率高，PKCS7Padding可支持IOS加解密
                //初始化，此方法可以采用三种方式，按加密算法要求来添加。（1）无第三个参数（2）第三个参数为SecureRandom random = new SecureRandom();中random对象，随机数。(AES不可采用这种方法)（3）采用此代码中的IVParameterSpec
                //加密时使用:ENCRYPT_MODE;  解密时使用:DECRYPT_MODE;
                cipher.init(Cipher.ENCRYPT_MODE, key); //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
                //加密操作,返回加密后的字节数组，然后需要编码。主要编解码方式有Base64, HEX, UUE,7bit等等。此处看服务器需要什么编码方式
                byte[] encryptedData = cipher.doFinal(cleartext.getBytes(CODE_TYPE));
    
                return new BASE64Encoder().encode(encryptedData);
            } catch (Exception e) {
                e.printStackTrace();
                return "";
            }
        }
    
        /**
         * 解密
         *
         * @param encrypted
         * @return
         */
        public static String decrypt(String encrypted) {
            try {
                byte[] byteMi = new BASE64Decoder().decodeBuffer(encrypted);
                IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
                SecretKeySpec key = new SecretKeySpec(
                        AES_KEY.getBytes(), "AES");
                Cipher cipher = Cipher.getInstance(AES_TYPE);
                //与加密时不同MODE:Cipher.DECRYPT_MODE
                cipher.init(Cipher.DECRYPT_MODE, key);  //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
                byte[] decryptedData = cipher.doFinal(byteMi);
                return new String(decryptedData, CODE_TYPE);
            } catch (Exception e) {
                e.printStackTrace();
                return "";
            }
        }
    
        /**
         * 测试
         *
         * @param args
         * @throws Exception
         */
        public static void main(String[] args) throws Exception {
            String content = "你笑起来真好看";
            test(content);
        }
    
        public static void test(String content) throws UnsupportedEncodingException{
            System.out.println("加密内容：" + content);
            //字节数
            int num = content.getBytes(CODE_TYPE).length;
            System.out.println("加密内容字节数: " + num);
            System.out.println("加密内容是否16倍数: " + (num%16 == 0 ? true : false));
    
            //字节补全
            if(AES_TYPE.equals("AES/ECB/NoPadding")){
                System.out.println();
                content = completionCodeFor16Bytes(content);
                System.out.println("加密内容补全后: "+content);
            }
    
            System.out.println();
    
            // 加密
            String encryptResult = encrypt(content);
            content = new String(encryptResult);
            System.out.println("加密后：" + content);
    
            System.out.println();
    
            // 解密
            String decryptResult = decrypt(encryptResult);
            content = new String(decryptResult);
            //还原
            if(AES_TYPE.equals("AES/ECB/NoPadding")){
                System.out.println("解密内容还原前: "+content);
                content = resumeCodeOf16Bytes(content);
            }
    
            System.out.println("解密完成后：" + content);
        }
    
    
    
    
        //NoPadding
        //补全字符
        public static String completionCodeFor16Bytes(String str) throws UnsupportedEncodingException{
            int num = str.getBytes(CODE_TYPE).length;
            int index = num%16;
            //进行加密内容补全操作, 加密内容应该为 16字节的倍数, 当不足16*n字节是进行补全, 差一位时 补全16+1位
            //补全字符 以 $ 开始,$后一位代表$后补全字符位数,之后全部以0进行补全;
            if(index != 0){
                StringBuffer sbBuffer = new StringBuffer(str);
                if(16-index == 1){
                    sbBuffer.append("$" + consult[16-1] + addStr(16-1-1));
                }else{
                    sbBuffer.append("$" + consult[16-index-1] + addStr(16-index-1-1));
                }
                str = sbBuffer.toString();
            }
            return str;
        }
    
        //追加字符
        public static String addStr(int num){
            StringBuffer sbBuffer = new StringBuffer("");
            for (int i = 0; i < num; i++) {
                sbBuffer.append("0");
            }
            return sbBuffer.toString();
        }
    
    
        //还原字符(进行字符判断)
        public static String resumeCodeOf16Bytes(String str){
            int indexOf = str.lastIndexOf("$");
            if(indexOf == -1){
                return str;
            }
            String trim = str.substring(indexOf+1,indexOf+2).trim();
            int num = 0;
            for (int i = 0; i < consult.length; i++) {
                if(trim.equals(consult[i])){
                    num = i;
                }
            }
            if(num == 0){
                return str;
            }
            return str.substring(0,indexOf).trim();
        }
    
    }

转载于:https://www.cnblogs.com/xiaowangxiao/p/11416713.html