Correct usage posture of encryption and decryption DES in php

Foreword: In daily development, we often encrypt key characters, maybe for security or for standardization. Today we will use DES encryption correctly

Task flow chart

Fragment 1

Just do it, I started writing des encryption code as follows

class DES
{
    var $key;
    var $iv; //偏移量
 
    function DES( $key, $iv=0 ) {
        //key长度8例如:1234abcd
        $this->key = $key;
        if( $iv == 0 ) {
            $this->iv = $key;
        } else {
            $this->iv = $iv; //mcrypt_create_iv ( mcrypt_get_block_size (MCRYPT_DES, MCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM );
        }
    }
 
    function encrypt($str) {
        //加密，返回大写十六进制字符串
        $size = mcrypt_get_block_size ( MCRYPT_DES, MCRYPT_MODE_CBC );
        $str = $this->pkcs5Pad ( $str, $size );
        return strtoupper( bin2hex( mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_ENCRYPT, $this->iv ) ) );
    }
 
    function decrypt($str) {
        //解密
        $strBin = $this->hex2bin( strtolower( $str ) );
        $str = mcrypt_cbc( MCRYPT_DES, $this->key, $strBin, MCRYPT_DECRYPT, $this->iv );
        $str = $this->pkcs5Unpad( $str );
        return $str;
    }
 
    function hex2bin($hexData) {
        $binData = "";
        for($i = 0; $i < strlen ( $hexData ); $i += 2) {
            $binData .= chr ( hexdec ( substr ( $hexData, $i, 2 ) ) );
        }
        return $binData;
    }
 
    function pkcs5Pad($text, $blocksize) {
        $pad = $blocksize - (strlen ( $text ) % $blocksize);
        return $text . str_repeat ( chr ( $pad ), $pad );
    }
 
    function pkcs5Unpad($text) {
        $pad = ord ( $text {strlen ( $text ) - 1} );
        if ($pad > strlen ( $text ))
            return false;
        if (strspn ( $text, chr ( $pad ), strlen ( $text ) - $pad ) != $pad)
            return false;
        return substr ( $text, 0, - 1 * $pad );
    }
}

Test code

<?php
header("Content-type: text/html; charset=utf-8");
error_reporting(0);
require "DES5.php";
// 秘钥
$key = &#39;MOxinrui&#39;;
$crypt = new DES5($key);
$str = &#39;podsmia&#39;;
echo "原字符是".$str.&#39;<br>&#39;;
$encrypt_str = $crypt->encrypt($str);
echo "加密后的字符是".$encrypt_str.&#39;<br>&#39;;
$decrypt_str= $crypt->decrypt($encrypt_str);
echo "解密后的字符是".$decrypt_str.&#39;<br>&#39;;

Effect

原字符是podsmia
加密后的字符是9490E64136137FD8
解密后的字符是podsmia

After a few days, I had nothing to do , continue to run the code

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; DES5 has a deprecated constructor in D:\phpstudy_pro\WWW\des\ DES5.php on line 2

The original characters are podsmia

Fatal error: Uncaught Error: Call to undefined function mcrypt_get_block_size() in D:\phpstudy_pro\WWW\des \DES5.php:19 Stack trace: #0 D:\phpstudy_pro\WWW\des\1.php(10): DES5->encrypt('podsmia') #1 {main} thrown in D:\phpstudy_pro\WWW \des\DES5.php on line 19

reported fatalerror to me. This is unscientific. I didn’t move anything. What's going on? After some research later. It was found that it was a problem with the php version. I ran it successfully before because I was using php5.5, but this time I got an error and I was using php7.2. Then I need to find an alternative. . Next, watch my operation

Fragment 2

<?php
class DES7
{
    //要改的加密
    public function desEncrypt($str,$key) {
        $iv = $key;
        $data = openssl_encrypt($str,"DES-CBC",$key,OPENSSL_RAW_DATA,$iv);
        $data = strtolower(bin2hex($data));
        return $data;
    }
 
    //要改的解密
    public function desDecrypt($str,$key) {
        $iv = $key;
        return openssl_decrypt (hex2bin($str), &#39;DES-CBC&#39;, $key, OPENSSL_RAW_DATA,$iv);
    }
}

Test code

<?php
header("Content-type: text/html; charset=utf-8");
//error_reporting(0);
// 秘钥
require "DES7.php";
$key = &#39;MOxinrui&#39;;
$crypt = new DES7($key);
$str = &#39;问哪个&#39;;
echo "原字符是".$str.&#39;<br>&#39;;
$encrypt_str = $crypt->desEncrypt($str,$key);
echo "加密后的字符是".$encrypt_str.&#39;<br>&#39;;
$decrypt_str= $crypt->desDecrypt($encrypt_str,$key);
echo "解密后的字符是".$decrypt_str.&#39;<br>&#39;;

Effect

原字符是问哪个
加密后的字符是074b8beee21eefca7ec3a60cb8edda18
解密后的字符是问哪个

The problem is solved perfectly. If you encounter this kind of problem in the future, you can just copy my code, which is convenient and trouble-free.

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