PHP加密解密函数

PHP加密解密函数

 

/**

• 加密函数
  *
• @param string $txt 需要加密的字符串
• @param string $key 密钥
• @return string 返回加密结果
  */
  function encrypt($txt, $key = ‘’){
  if (empty($txt)) return $txt;
  if (empty($key)) $key = md5(MD5KEY);
  $chars = “ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-.”;
  $ikey =”-x6g6ZWm2G9g_vr0Bo.pOq3kRIxsZ6rm”;
  $nh1 = rand(0,64);
  $nh2 = rand(0,64);
  $nh3 = rand(0,64);
  $ch1 = $chars{$nh1};
  $ch2 = $chars{$nh2};
  $ch3 = $chars{$nh3};
  $nhnum = $nh1 + $nh2 + $nh3;
  $knum = 0;$i = 0;
  while(isset($key{$i})) $knum +=ord($key{$i++});
  $mdKey = substr(md5(md5(md5($key.$ch1).$ch2.$ikey).$ch3),$nhnum%8,$knum%8 + 16);
  $txt = base64encode(time().’‘.$txt);
  $txt = strreplace(array(‘+’,’/‘,’=’),array(‘-‘,’‘,’.’),$txt);
  $tmp = ‘’;
  $j=0;$k = 0;
  $tlen = strlen($txt);
  $klen = strlen($mdKey);
  for ($i=0; $i<$tlen; $i++) {
  $k = $k == $klen ? 0 : $k;
  $j = ($nhnum+strpos($chars,$txt{$i})+ord($mdKey{$k++}))%64;
  $tmp .= $chars{$j};
  }
  $tmplen = strlen($tmp);
  $tmp = substr_replace($tmp,$ch3,$nh2 % ++$tmplen,0);
  $tmp = substr_replace($tmp,$ch2,$nh1 % ++$tmplen,0);
  $tmp = substr_replace($tmp,$ch1,$knum % ++$tmplen,0);
  return $tmp;
  }

/**

• 解密函数
  *
• @param string $txt 需要解密的字符串
• @param string $key 密匙

• @return string 字符串类型的返回结果
  */
  function decrypt($txt, $key = ‘’, $ttl = 0){
  if (empty($txt)) return $txt;
  if (empty($key)) $key = md5(MD5_KEY);

  $chars = “ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_.”;
  $ikey =”-x6g6ZWm2G9g_vr0Bo.pOq3kRIxsZ6rm”;
  $knum = 0;$i = 0;
  $tlen = @strlen($txt);
  while(isset($key{$i})) $knum +=ord($key{$i++});
  $ch1 = @$txt{$knum % $tlen};
  $nh1 = strpos($chars,$ch1);
  $txt = @substr_replace($txt,’’,$knum % $tlen–,1);
  $ch2 = @$txt{$nh1 % $tlen};
  $nh2 = @strpos($chars,$ch2);
  $txt = @substr_replace($txt,’’,$nh1 % $tlen–,1);
  $ch3 = @$txt{$nh2 % $tlen};
  $nh3 = @strpos($chars,$ch3);
  $txt = @substr_replace($txt,’’,$nh2 % $tlen–,1);
  $nhnum = $nh1 + $nh2 + $nh3;
  $mdKey = substr(md5(md5(md5($key.$ch1).$ch2.$ikey).$ch3),$nhnum % 8,$knum % 8 + 16);
  $tmp = ‘’;
  $j=0; $k = 0;
  $tlen = @strlen($txt);
  $klen = @strlen($mdKey);
  for ($i=0; $i<$tlen; $i++) {
  $k = $k == $klen ? 0 : $k;
  $j = strpos($chars,$txt{$i})-$nhnum - ord($mdKey{$k++});
  while ($j<0) $j+=64;
  $tmp .= $chars{$j};
  }
  $tmp = strreplace(array(‘-‘,’‘,’.’),array(‘+’,’/‘,’=’),$tmp);
  $tmp = trim(base64_decode($tmp));

  if (pregmatch(“/\d{10}/s”,substr($tmp,0,11))){
  if ($ttl > 0 && (time() - substr($tmp,0,11) > $ttl)){
  $tmp = null;
  }else{
  $tmp = substr($tmp,11);
  }
  }
  return $tmp;
  }