replaceenc['/'.$i.'/'] = $this->replacement{$i};
            $this->replacedec['/'.$this->replacement{$i}.'/'] = $i;
        }
    }
    public function encrypt($str) {
        return preg_replace(
            array_keys($this->replaceenc),
            $this->replaceenc,
            $this->mynotin(preg_replace(/(.)(.)/, ${2}${1}, $str))
        );
    }
    public function decrypt($str) {
        return preg_replace(/(.)(.)/, ${2}${1},
            $this->mynotout(preg_replace(array_keys($this->replacedec),$this->replacedec,$str))
        );
    }
    private function mynotin($str) {
        $str_out = ;
        $i = 0;
        while(isset($str{7*$i})) {
            $str_out .= (($this->prefix.substr($str, $i*7, 7))+0)^$this->match;
            $i++;
        }
        return $str_out;
    }
    private function mynotout($str) {
        $str_out = ;
        $i = 0;
        while(isset($str{8*$i})) {
            $str_out .= substr((substr($str, $i*8, 8)+0)^$this->match, 1);
            $i++;
        }
        return $str_out;
    }
}
?> 以上就介绍了php5下载 php5数字型字符串加解密代码，包括了php5下载方面的内容，希望对php教程有兴趣的朋友有所帮助。