对称密码的编程使用（DES、3DES、AES）

逃离我推掉我的手 2022-09-28 14:25 223阅读 0赞

## 对称密码的概念    ##

*  加密密钥和解密密钥相同，对于大多数对称密码算法，加解密过程互逆
 *  加解密通信模型

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*  特点：算法公开、计算量小、加密速度快、加密效率高
 *  弱点：双方都使用同样密钥，安全性得不到保证

## DES 算法的编程使用（密钥偏短（56位）、生命周期短）    ##

package com.crypt.des;
    
    import com.crypt.ByteToHexUtil;
    
    import javax.crypto.Cipher;
    import javax.crypto.KeyGenerator;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    
    /**
     * des加密
     * Created by zhangweixiang on 4/17/2016.
     */
    public class DESUtil {
    
        /**
         * 生成desckey
         * @param type
         * @return
         * @throws Exception
         */
        public static byte[] generateKey(String type) throws Exception {
            KeyGenerator keyGenerator = KeyGenerator.getInstance(type);
            keyGenerator.init(56);
            SecretKey secretKey = keyGenerator.generateKey();
            return  secretKey.getEncoded();
        }
    
        /**
         * 通过指定的deskey加密
         * @param data 加密的数据
         * @param key 秘钥
         * @param type 加密方式
         * @return 加密信息
         * @throws Exception
         */
        public static byte[] encrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.ENCRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        /**
         * des解密
         * @param data 需要解密的数据
         * @param key 解密秘钥
         * @param type 类型
         * @return 解密后的结果
         * @throws Exception
         */
        public static byte[] decrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.DECRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        public static void main(String[] args) throws Exception {
            String data = "test desc";
            String type = "DES";// DES/ECB/PKCS5Padding
            byte[] key = DESUtil.generateKey(type);
            byte[] encData = DESUtil.encrypt(data.getBytes(),key,type);
            String encDataStr = ByteToHexUtil.bytesToHexString(encData);
            System.out.println(data+">>des encrypt>>"+encDataStr);
    
            byte[] decData = DESUtil.decrypt(encData,key,type);
            System.out.println(encDataStr+">>des decrypt>>"+new String(decData));
        }
    }

## 3DES 算法的编程使用    ##

将密钥长度增至112位或168位，通过增加迭代次数提高安全性

缺点：处理速度较慢、密钥计算时间较长、加密效率不高

package com.crypt.des;
    
    import com.crypt.ByteToHexUtil;
    
    import javax.crypto.Cipher;
    import javax.crypto.KeyGenerator;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    
    /**
     * 3des加密
     * Created by zhangweixiang on 4/17/2016.
     */
    public class TripleDESUtils {
    
        /**
         * 生成3desckey
         * @param type
         * @return
         * @throws Exception
         */
        public static byte[] generateKey(String type) throws Exception {
            KeyGenerator keyGenerator = KeyGenerator.getInstance(type);
            keyGenerator.init(112);//128 168
            SecretKey secretKey = keyGenerator.generateKey();
            return  secretKey.getEncoded();
        }
    
        /**
         * 通过指定的3deskey加密
         * @param data 加密的数据
         * @param key 秘钥
         * @param type 加密方式
         * @return 加密信息
         * @throws Exception
         */
        public static byte[] encrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.ENCRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        /**
         * 3des解密
         * @param data 需要解密的数据
         * @param key 解密秘钥
         * @param type 类型
         * @return 解密后的结果
         * @throws Exception
         */
        public static byte[] decrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.DECRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        public static void main(String[] args) throws Exception {
            String data = "test desc";
            String type = "DESede";// DES/ECB/PKCS5Padding
            byte[] key = TripleDESUtils.generateKey(type);
            byte[] encData = TripleDESUtils.encrypt(data.getBytes(),key,type);
            String encDataStr = ByteToHexUtil.bytesToHexString(encData);
            System.out.println(data+">>3des encrypt>>"+encDataStr);
    
            byte[] decData = TripleDESUtils.decrypt(encData,key,type);
            System.out.println(encDataStr+">>3des decrypt>>"+new String(decData));
        }
    }

## AES 算法的编程使用    ##

1.AES：高级数据加密标准，能够有效抵御已知的针对DES算法的所有攻击

2.特点：密钥建立时间短、灵敏性好、内存需求低、安全性高

package com.crypt.des;
    
    import com.crypt.ByteToHexUtil;
    
    import javax.crypto.Cipher;
    import javax.crypto.KeyGenerator;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    
    /**
     * aes加密/解密
     * Created by zhangweixiang on 4/17/2016.
     */
    public class AESUtil {
    
        /**
         * 生成adesckey
         * @param type
         * @return
         * @throws Exception
         */
        public static byte[] generateKey(String type) throws Exception {
            KeyGenerator keyGenerator = KeyGenerator.getInstance(type);
            keyGenerator.init(128);//默认为128位，如果使用192 256则需获取无政策文件(从oracle官网下载UnlimitedJECPolicyJDK7解压后将
                                    //其中的2个jar拷贝到jre下的lib下的security中即可 )
            SecretKey secretKey = keyGenerator.generateKey();
            return  secretKey.getEncoded();
        }
    
        /**
         * 通过指定的aeskey加密
         * @param data 加密的数据
         * @param key 秘钥
         * @param type 加密方式
         * @return 加密信息
         * @throws Exception
         */
        public static byte[] encrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.ENCRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        /**
         * aes解密
         * @param data 需要解密的数据
         * @param key 解密秘钥
         * @param type 类型
         * @return 解密后的结果
         * @throws Exception
         */
        public static byte[] decrypt(byte[] data,byte[] key,String type) throws Exception {
            SecretKey secretKey = new SecretKeySpec(key,type);
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.DECRYPT_MODE,secretKey);
            return cipher.doFinal(data);
        }
    
        public static void main(String[] args) throws Exception {
            String data = "test desc";
            String type = "AES";//AES/ECB/PKCS5Padding
            byte[] key = AESUtil.generateKey(type);
            byte[] encData = AESUtil.encrypt(data.getBytes(),key,type);
            String encDataStr = ByteToHexUtil.bytesToHexString(encData);
            System.out.println(data+">>aes encrypt>>"+encDataStr);
    
            byte[] decData = AESUtil.decrypt(encData,key,type);
            System.out.println(encDataStr+">>aes decrypt>>"+new String(decData));
        }
    }

[Center]: /images/20220708/90b51a0e303a4b549f737dc785a34710.png