rc4.php

<?php

class rc4crypt
{

    function endecrypt( $pwd, $data, $case = "encrypt" )
    {
        if ( $case == "decrypt" )
        {
            $data = urldecode( $data );
        }
        $key[] = "";
        $box[] = "";
        $temp_swap = "";
        $pwd_length = 0;
        $pwd_length = strlen( $pwd );
        $i = 0;
        for ( ; $i <= 255; ++$i )
        {
            $key[$i] = ord( substr( $pwd, $i % $pwd_length, 1 ) );
            $box[$i] = $i;
        }
        $x = 0;
        $i = 0;
        for ( ; $i <= 255; ++$i )
        {
            $x = ( $x + $box[$i] + $key[$i] ) % 256;
            $temp_swap = $box[$i];
            $box[$i] = $box[$x];
            $box[$x] = $temp_swap;
        }
        $temp = "";
        $k = "";
        $cipherby = "";
        $cipher = "";
        $a = 0;
        $j = 0;
        $i = 0;
        for ( ; $i < strlen( $data ); ++$i )
        {
            $a = ( $a + 1 ) % 256;
            $j = ( $j + $box[$a] ) % 256;
            $temp = $box[$a];
            $box[$a] = $box[$j];
            $box[$j] = $temp;
            $k = $box[( $box[$a] + $box[$j] ) % 256];
            $cipherby = ord( substr( $data, $i, 1 ) ) ^ $k;
            $cipher .= chr( $cipherby );
        }
        if ( $case == "decrypt" )
        {
            $cipher = urldecode( urlencode( $cipher ) );
        }
        else
        {
            $cipher = urlencode( $cipher );
        }
        return $cipher;
    }

    function decrypt( $key, $data )
    {
        return $this->endecrypt( $key, base64_decode( $data ), "decrypt" );
    }

    function encrypt( $key, $data )
    {
        return base64_encode( $this->endecrypt( $key, $data, "encrypt" ) );
    }

}

new rc4crypt( )->rc4crypt( );
$rc4 = new rc4crypt( );
?>