ClassGost.php

<?php

/** Êëàññ îñóùåñòâëÿþùèé ðàáîòó ñ øèôðîì ÃÎÑÒ 28147-89 (øèôðîâàíèå/äåøèôðîâàííèå äàííûõ)
 *
 * @author IntSys
 * @copyright Copyright (c) 2011-2013, IntSys, intsystem.org
 */
class ClassGost{
    /** Êîëè÷åñòî èòòåðàöèé îñíîâíîãî øàãà êðèïòîîáðàçîâàíèÿ
     */
    const CNT_MAIN_STEP=32;

    /** Òàáëèöà çàìåí
     *
     * @var array
     */
    protected $s_block=array(
        array(6,12,7,1,5,15,13,8,4,10,9,14,0,3,11,2),
        array(14,11,4,12,6,13,15,10,2,3,8,1,0,7,5,9),
        array(13,11,4,1,3,15,5,9,0,10,14,7,6,8,2,12),
        array(7,13,10,1,0,8,9,15,14,4,6,12,11,2,5,3),
        array(1,15,13,0,5,7,10,4,9,2,3,14,6,11,8,12),
        array(4,10,9,2,13,8,0,14,6,11,1,12,7,15,5,3),
        array(4,11,10,0,7,2,1,13,3,6,8,5,9,12,15,14),
        array(5,8,1,13,10,3,4,2,14,15,12,7,6,0,9,11),

    );

    /** Êëþ÷
     *
     * @var array
     */
    protected $k_block=array (
        0x00000000,
        0x00000000,
        0x00000000,
        0x00000000,
        0x00000000,
        0x00000000,
        0x00000000,
        0x00000000,
    );


    /** Çàøèôðîâàòü äàííûå
     *
     * @param string $data äàííûå äëÿ øèôðîâàíèÿ
     * @param mixed $key êëþ÷ øèôðîâàíèÿ
     * @param array $table òàáëèöà çàìåí
     * @return mixed âîçâðàùàåò çàøèôðîâàííóþ ñòðîêó, èëè false â ñëó÷àå íåóäà÷è
     */
    function Encode($data, $key=null, $table=null){
        if(!is_null($key)){
            if(!$this->SetKey($key)){
                return false;
            }
        }

        if(!is_null($table)){
            if(!$this->SetTableReplace($table)){
                return false;
            }
        }

        $blocks=$this->LoadData2Blocks($data);
        $keys=$this->LoadKeysArray(self::CNT_MAIN_STEP);

        $result='';

        foreach($blocks as $block){
            $result.=$this->Global_MainStep($block, $keys);

        }

        return $result;
    }

    /** Ðàñøèôðîâàòü äàííûå
     *
     * @param string $data çàøèôðîâàííûå äàííûå
     * @param mixed $key êëþ÷ øèôðîâàíèÿ
     * @param array $table òàáëèöà çàìåí
     * @return mixed âîçâðàùàåò èñõîäíûå äàííûå, èëè false â ñëó÷àå íåóäà÷è
     */
    function Decode($data, $key=null, $table=null){
        if(!is_null($key)){
            if(!$this->SetKey($key)){
                return false;
            }
        }

        if(!is_null($table)){
            if(!$this->SetTableReplace($table)){
                return false;
            }
        }

        $blocks=$this->LoadData2Blocks($data);
        $keys=array_reverse($this->LoadKeysArray(self::CNT_MAIN_STEP));

        $result='';
        foreach($blocks as $block){
            $result.=$this->Global_MainStep($block, $keys);
        }

        return $result;
    }

    /** Óñòàíîâèòü êëþ÷ øèôðîâàíèÿ<br><br>
     * Âîçìîæíî óêàçàòü êëþ÷ â äâóõ ôîðìàòàõ:<br>
     *  - Ñòðîêà äëèííîé â 32 áàéòà<br>
     *  - Ìàññèâ èç 8 ýëåìåíòîâ, ãäå êàæäûé ýëåìåíò - 4 áàéòîâîå ÷èñëî integer<br><br>
     * Ïðè ýòîì ëþáîå îòêëîíåíèå îò äàííûõ ôîðìàòîâ áóäåò âûçûâàòü îøèáêó
     *
     * @param mixed $key êëþ÷ øèôðîâàíèÿ
     * @return boolen âîçâðàùàåò true åñëè óäàëîñü óñòàíîâèòü êëþ÷ øèôðîâàíèÿ, false - åñëè ïðîèçîøëà îøèáêà
     */
    function SetKey($key){
        if(is_string($key)){
            if(strlen($key)!==32){
                trigger_error(__METHOD__.': "$key" length must be equal to 256 bits (32 bytes)', E_USER_WARNING);
                return false;
            }

            $new_key=array();
            for($i=0; $i<32; $i+=4){
    //          $tmp=(int)hexdec(bin2hex(substr($key, ($i*4), 4)));
                $tmp=(int)hexdec(bin2hex(substr($key, ($i), 4)));
                $new_key[]=$tmp;
            }

            $this->k_block=$new_key;
            return true;
        }elseif(is_array($key)){
            if(count($key)!=8){
                trigger_error(__METHOD__.': count of elements in the array "$key" must be equal to 8', E_USER_WARNING);
                return false;
            }
            $new_key=array();
            foreach($key as $k => $val){
                if(!is_integer($val)){
                    trigger_error(__METHOD__.': every element of the array "$key" must be integer. The array element "$table['.htmlspecialchars($k).']" is not an integer.', E_USER_WARNING);
                    return false;
                }

                $new_key[]=$val;
            }

            $this->k_block=$new_key;
            return true;
        }else{
            trigger_error(__METHOD__.': unknown "$Key" format. "$key" must be array[8] of integer or 32-bytes string.', E_USER_WARNING);
            return false;
        }
    }

    /** Óñòàíîâèòü òàáëèöó çàìåí.<br>
     * Ôîðìàò òàáëèöû çàìåí - ìàòðèöà ðàçìåðíîñòüþ 8x16,
     * êàæäûé åå ýëåìåíò áîëüøå ëèáî ðàâåí 0 è ìåíüøå ëèáî ðàâåí 15,
     * ïðè ýòîì â êàæäîé ñòðîêå íå äîëæíî áûòü ïîâòîðÿþùèõñÿ çíà÷åíèé.<br><br>
     * Òàêæå îáðàòèòå âíèìàíèå ÷òî íåïðàâèëüíûé âûáîð òàáëèöû çàìåí, ìîæåò
     * ïðèâåñòè ê ñíèæåíèþ ñòîéêîñòè øèôðà.
     *
     * @example
     * Ïðèìåð òàáëèöû:<br>
     * array(6 ,12,7 ,1 ,5 ,15,13,8 ,4 ,10,9 ,14,0 ,3 ,11,2 ),<br>
     * array(14,11,4 ,12,6 ,13,15,10,2 ,3 ,8 ,1 ,0 ,7 ,5 ,9 ),<br>
     * array(13,11,4 ,1 ,3 ,15,5 ,9 ,0 ,10,14,7 ,6 ,8 ,2 ,12),<br>
     * array(7 ,13,10,1 ,0 ,8 ,9 ,15,14,4 ,6 ,12,11,2 ,5 ,3 ),<br>
     * array(1 ,15,13,0 ,5 ,7 ,10,4 ,9 ,2 ,3 ,14,6 ,11,8 ,12),<br>
     * array(4 ,10,9 ,2 ,13,8 ,0 ,14,6 ,11,1 ,12,7 ,15,5 ,3 ),<br>
     * array(4 ,11,10,0 ,7 ,2 ,1 ,13,3 ,6 ,8 ,5 ,9 ,12,15,14),<br>
     * array(5 ,8 ,1 ,13,10,3 ,4 ,2 ,14,15,12,7 ,6 ,0 ,9 ,11),<br>
     *
     * @param array $table òàáëèöà çàìåí
     * @return boolean âîçâðàùàåò true åñëè óäàëîñü óñòàíîâèòü òàáëèöó çàìåí, false- åñëè ïðîèçîøëà îøèáêà
     */
    function SetTableReplace($table){
        if(!is_array($table)){
            trigger_error(__METHOD__.': "$table" must be array', E_USER_WARNING);
            return false;
        }

        if(count($table)!=8){
            trigger_error(__METHOD__.': count of elements in the array "$table" must be equal to 8', E_USER_WARNING);
            return false;
        }

        $i=0;
        $new_array=array();
        foreach($table as $key => $val){
            if(!is_array($val)){
                trigger_error(__METHOD__.': $table['.htmlspecialchars($key).'] must be array', E_USER_WARNING);
                return false;
            }

            if(count($val)!=16){
                trigger_error(__METHOD__.': count of elements in the array "$table['.htmlspecialchars($key).']" must be equal to 16', E_USER_WARNING);
                return false;
            }


            $new_val=array();
            foreach($val as $int_key => $int_val){
                if(!is_integer($int_val)){
                    trigger_error(__METHOD__.': every element of the array "$table['.htmlspecialchars($key).']" must be integer. The array element "$table['.htmlspecialchars($key).']['.htmlspecialchars($int_key).']" is not an integer.', E_USER_WARNING);
                    return false;
                }

                if($int_val>15 || $int_val<0){
                    trigger_error(__METHOD__.': every element of the array "$table['.htmlspecialchars($key).']" must be greater than or equal to 0 and less than or equal to 15. The array element "$table['.htmlspecialchars($key).']['.htmlspecialchars($int_key).']" is not in this range.', E_USER_WARNING);
                    return false;
                }
                $new_val[]=$int_val;
            }

            $new_array[$i]=$new_val;
            $i++;
        }


        $this->s_block=$new_array;
        return true;
    }

    /** Îñíîâíîé øàã øèôðîîáðàçîâàíèÿ
     *
     * @param string $block øèôðóåìûé áëîê
     * @param array $keys ïîäãîòîâëåííûé ìàññèâ ñ êëþ÷àìè
     * @param intger $cnt_repeat [îïöèîíàëüíî] êîëè÷åñòâî ïðåîáðàçîâàíèé
     * @return string
     */
    protected function Global_MainStep($block, $keys, $cnt_repeat=self::CNT_MAIN_STEP){
        $this->Global_BlockExplode($block, $n1, $n2);

        if(count($keys)<$cnt_repeat){
            $cnt_repeat=count($keys);
        }

        for($i=0; $i<$cnt_repeat; $i++){
            $val=$this->Global_SummMod32($n1, $keys[$i]);

            $val=$this->Global_BlockReplace($val);

            $val=$this->Global_BlockCycleShift($val, 21);

            $val=$val ^ $n2;

            $n2=$n1;
            $n1=$val;
        }

        $this->Global_BlockImplode($block, $n2, $n1);
        return $block;
    }

    /** Ôóíêöèÿ öèêëè÷íîãî ïîáèòîâîãî ñäâèãà âïðàâî
     *
     * @param integer $block
     * @param integer $bits êîëè÷åñòâî áèòîâ äëÿ ñäâèãà
     * @return integer
     */
    protected function Global_BlockCycleShift($block, $bits){
        if($bits>0){
            $a=$bits;
            $b=32-$a;
            $block=(($block >> $a) & ~(-pow(2,$b)))^($block << $b);
        }
        return $block;
    }

    /** Çàìåíà ïî òàáëèöå çàìåí
     *
     * @param integer $block òåêóùèé áëîê äëÿ çàìåíû
     * @return integer
     */
    protected function Global_BlockReplace($block){
        $new_block=0;

        for($i=0; $i<8; $i++){
            //Âû÷ëåíÿåì íóæíûå 4 áèòà ïîä çàìåíó
            $rem=$block>>(4*($i+1));
            $rem=$rem<<(4*($i+1));

            if($i==7){
                $hex=$rem;
            }else{
                $hex=$block-$rem;
                $block=$rem;
            }

            $hex=$this->Global_BlockCycleShift($hex,(4*$i));

            //Íàõîäèì íà êàêîå ÷èñëî åãî çàìåíÿòü ïî òàáëèöå çàìåí
            $replace=$this->s_block[$i][$hex];

            //Çàìåíÿåì
            $new_block=$new_block + (pow(16, $i)*$replace);
        }

        return $new_block;
    }

    /** Ñóììèðîâàíèå äâóõ ÷èñåë ïî ìîäóëþ 32
     *
     * @param integer $bin1 ÷èñëî (4 áàéòà)
     * @param integer $bin2 ÷èñëî (4 áàéòà)
     * @return integer ðåçóëüòàò âû÷èñëåíèÿ (4 áàéòà)
     */
    protected function Global_SummMod32($bin1, $bin2){
        $summ=$this->NormalizeInteger32(intval($bin1 + $bin2));

        return $summ;
    }

    /** Ðàçáèåíèå áëîêà íà "ïðàâóþ" è "ëåâóþ" ÷àñòü
     *
     * @param string $block âõîäíîé áëîê (8 áàéò)
     * @param &integer $left ëåâàÿ ÷àñòü (íàêîïèòåëü N1) (4 áàéòà)
     * @param &integer $right ïðàâàÿ ÷àñòü (íàêîïèòåëü N2) (4 áàéòà)
     */
    protected function Global_BlockExplode($block, &$left, &$right){
        $left='';
        $right='';

        $left=substr($block, 0, 4);
        $right=substr($block, 4, 4);

        $left =hexdec(bin2hex($left ));
        $right=hexdec(bin2hex($right));
    }

    /** Ðàçáèåíèå áëîêà íà "ïðàâóþ" è "ëåâóþ" ÷àñòü
     *
     * @param &string $block âõîäíîé áëîê (8 áàéò)
     * @param integer $left ëåâàÿ ÷àñòü (íàêîïèòåëü N1) (4 áàéòà)
     * @param integer $right ïðàâàÿ ÷àñòü (íàêîïèòåëü N2) (4 áàéòà)
     */
    protected function Global_BlockImplode(&$block, $left, $right){
        $left =sprintf("%08x", $left );
        $right=sprintf("%08x", $right);

        $block='';

        $arr=str_split($left, 2);
        foreach($arr as $hex){
            $block.=chr(hexdec($hex));
        }

        $arr=str_split($right, 2);
        foreach($arr as $hex){
            $block.=chr(hexdec($hex));
        }
    }

    /** Ãåíåðèðóåì ìàññèâ ñ êëþ÷àìè
     *
     * @param integer $cnt_repeat êîëè÷åñòâî êëþ÷åé
     * @return array
     */
    protected function LoadKeysArray($cnt_repeat=self::CNT_MAIN_STEP){
        $key_block=array();
        for($i=0; $i<$cnt_repeat; $i++){
            if($i<($cnt_repeat-8)){
                $x=$i % 8;
            }else{
                $x=7 - ($i % 8);
            }
            $key_block[]=$this->k_block[$x];
        }

        return $key_block;
    }

    /** Ðàçáèâàåì äàííûå íà áëîêè ïî 64 áèòà (8 áàéò)
     *
     * @param string $data âõîäíûå äàííûå
     * @param integer $block_size [îïöèîíàëüíî] (64 - äåôîëò) ðàçìåðíîñòü áëîêîâ
     * @return array âûõîäíîé ìàññèâ ñ áëîêàìè
     */
    protected function LoadData2Blocks($data, $block_size=64){
        $blocks=array();

        $block_len=(int)$block_size / 8;

        for($i=0, $x=(ceil(strlen($data)/$block_len)); $i<$x; $i++){
            $blocks[$i]=substr($data, ($i*$block_len), $block_len);

            if($i==($x-1)){
                //Åñëè ïîñëåäíèé áëîê íå ïîëîí, òî äîïîëíÿåì åãî íóëÿìè
                $blocks[$i]=str_pad($blocks[$i], $block_len, chr(0), STR_PAD_RIGHT);

            }
        }

        return $blocks;
    }

    /** Ïðåâåäåíèå 64áèòíîãî integer ê "32áèòíîìó" íà 64áèòíûõ ñèñòåìàõ
     *
     * @param integer $number
     */
    private function NormalizeInteger32($number){
        static $is_64bit=null;

        $number=intval($number);

        if(is_null($is_64bit)){
            if(intval(2147483647+1)>0){
                $is_64bit=true;
            }else{
                $is_64bit=false;
            }
        }

        if($is_64bit){
            static $int=null;

            if(is_null($int)){
                $int=0;

                //Ãåíåðèðóåì ÷èñëî ó êîòîðîãî â äâîè÷íîì ïðåäñòàâëåíèè ìëàäøèå 32 áèòà - åäèíèöû, îñòàëüíûå - íóëè
                //
                // 32-áèòíûõ ñèñòåìàõ ýòî ÷èñëî "-1"
                //Â 64-áèòíûõ - "4294967295"
                for($i=0; $i<32; $i++){
                    $int=$int | (1<<$i);
                }
            }

            //Ïîáèòîâîå AND
            $number=intval($number & $int);
        }

        return $number;
    }
}