PHP：文字列を暗号化するアルゴリズムを作成する方法

Question

私は2つの方法（暗号化と復号化）であるアルゴリズムを作成したいと思っています。それぞれの文字が持つバイト数。

Exaple：

$string = "Hello"; 
$Array =[ 
'H' => 3827, 
'e' => 371, 
'l' => 472, 
'o' => 182 
]; 
(Encrypt): $string->encrypt->result: "48Hsj4adj373Hdue73" 
(Decrypt): "48Hsj4adj373Hdue73"->decrypt->result: "Hello" 

//How would I do it? 

私は解決策を見つけた：

class c 
    { 
     function a($k, $w){ 
      if($w === 0){ 
       return $k*13; 
      }elseif($w === 1){ 
       $arr = explode(",", $k); 
       $string = ""; 
       foreach($arr as $ke){ 
        $var = (int)$ke/13; 
        $string = $string.chr($var); 
       } 
       if(empty($string)){return "Error";}return $string; 
      } 
     } 
     function e($str){ 
      $c = str_split($str); 
      $string = ""; 
      foreach($c as $key=>$k){ 
       $ke = c::a(ord($k), 0); 
       $string = $string.(string)$ke.','; 
      } 
      $string = rtrim($string, ','); 
      return $string; 
     } 
     function d($str){ 
      return c::a($str, 1); 
     } 
    } 

Answer 1

は、通常のXOR暗号化とのFeistel暗号化方式でも見てみましょう。

class FeistelCipherHelper 
{ 
    /** 
    * @param  $str 
    * @param int $i 
    * @return string 
    */ 
    public static function encode($str, $i = 5) 
    { 
     $len = strlen($str); 
     if ($len % 2 !== 0) 
     { 
      $str = $str.' '; 
     } 
     $str = str_split($str, 2); 
     $hash = ''; 
     foreach ($str as $chr) 
     { 
      $l = ord(substr($chr, 0, 1)); 
      $r = ord(substr($chr, 1)); 
      FeistelCipherAlgorithm::encode($l, $r, $i); 
      $l = chr($l); 
      $r = chr($r); 
      $hash .= $l.$r; 
     } 
     $hash = trim($hash, ' '); 
     $hash = Base64Url::encode($hash); 

     return $hash; 
    } 

    /** 
    * @param  $hash 
    * @param int $i 
    * @return string 
    */ 
    public static function decode($hash, $i = 5) 
    { 
     $hash = Base64Url::decode($hash); 
     $len = strlen($hash); 
     if ($len % 2 !== 0) 
     { 
      $hash = $hash.' '; 
     } 
     $hash = str_split($hash, 2); 
     $str = ''; 
     foreach ($hash as $chr) 
     { 
      $l = ord(substr($chr, 0, 1)); 
      $r = ord(substr($chr, 1)); 
      FeistelCipherAlgorithm::decode($l, $r, $i); 
      $l = chr($l); 
      $r = chr($r); 
      $str .= $l.$r; 
     } 
     $str = trim($str, ' '); 

     return $str; 
    } 
} 

class XorHelper 
{ 
    /** 
    * @param  $str 
    * @param  $passw 
    * @param  $salt 
    * @return int|string 
    */ 
    public static function encode($str, $passw, $salt) 
    { 
     $str = XorAlgorithm::code($str, $passw, $salt); 
     $str = Base64Url::encode($str); 

     return $str; 
    } 

    /** 
    * @param  $str 
    * @param  $passw 
    * @param  $salt 
    * @return int|string 
    */ 
    public static function decode($str, $passw, $salt) 
    { 
     $str = Base64Url::decode($str); 
     $str = XorAlgorithm::code($str, $passw, $salt); 

     return $str; 
    } 
} 

class Base64Url 
{ 
    /** 
    * @param string $input 
    * @return string 
    */ 
    public static function encode($input) 
    { 
     $str = strtr(base64_encode($input), '+/', '-_'); 
     $str = str_replace('=', '', $str); 

     return $str; 
    } 

    /** 
    * @param string $input 
    * @return string 
    */ 
    public static function decode($input) 
    { 
     return base64_decode(strtr($input, '-_', '+/')); 
    } 
} 

class XorAlgorithm 
{ 
    public static function code($str, $passw = '', $salt = 'aeJRhN7840Xn') 
    { 
     $len = strlen($str); 
     $gamma = ''; 
     $n = $len > 100 ? 8 : 2; 
     while (strlen($gamma) < $len) 
     { 
      $gamma .= substr(pack('H*', sha1($passw.$gamma.$salt)), 0, $n); 
     } 

     return $str^$gamma; 
    } 
} 

class FeistelCipherAlgorithm 
{ 
    /** 
    * @param $block 
    * @param $key 
    * @return int 
    */ 
    public static function func($block, $key) 
    { 
     $val = ((2 * $block) + pow(2, $key)); 

     return $val; 
    } 

    /** 
    * @param  $left 
    * @param  $right 
    * @param int $steps 
    */ 
    public static function encode(&$left, &$right, $steps = 5) 
    { 
     $i = 1; 
     while ($i < $steps) 
     { 
      $temp = $right^static::func($left, $i); 
      $right = $left; 
      $left = $temp; 
      $i++; 
     } 

     $temp = $right; 
     $right = $left; 
     $left = $temp; 
    } 

    /** 
    * @param  $left 
    * @param  $right 
    * @param int $steps 
    */ 
    public static function decode(&$left, &$right, $steps = 5) 
    { 
     $i = $steps - 1; 
     while ($i > 0) 
     { 
      $temp = $right^static::func($left, $i); 
      $right = $left; 
      $left = $temp; 
      $i--; 
     } 
     $temp = $right; 
     $right = $left; 
     $left = $temp; 
    } 
}