这段代码怎样解密，又是如何加密的？

Question

太长了发布不上来，全部代码：http://bbs.php.cn/read-htm-tid-44302.html
下面是部分代码<?php    if (!function_exists("T7FC56270E7A70FA81A5935B72EACBE29"))  {   function T7FC56270E7A70FA81A5935B72EACBE29($TF186217753C37B9B9F958D906208506E)   {    $TF186217753C37B9B9F958D906208506E = base64_decode($TF186217753C37B9B9F958D906208506E);    $T7FC56270E7A70FA81A5935B72EACBE29 = 0;    $T9D5ED678FE57BCCA610140957AFAB571 = 0;    $T0D61F8370CAD1D412F80B84D143E1257 = 0;    $TF623E75AF30E62BBD73D6DF5B50BB7B5 = (ord($TF186217753C37B9B9F958D906208506E[1]) << 8) + ord($TF186217753C37B9B9F958D906208506E[2]);    $T3A3EA00CFC35332CEDF6E5E9A32E94DA = 3;    $T800618943025315F869E4E1F09471012 = 0;    $TDFCF28D0734569A6A693BC8194DE62BF = 16;    $TC1D9F50F86825A1A2302EC2449C17196 = "";    $TDD7536794B63BF90ECCFD37F9B147D7F = strlen($TF186217753C37B9B9F958D906208506E);    $TFF44570ACA8241914870AFBC310CDB85 = __FILE__;    $TFF44570ACA8241914870AFBC310CDB85 = file_get_contents($TFF44570ACA8241914870AFBC310CDB85);    $TA5F3C6A11B03839D46AF9FB43C97C188 = 0;    preg_match(base64_decode("LyhwcmludHxzcHJpbnR8ZWNobykv"), $TFF44570ACA8241914870AFBC310CDB85, $TA5F3C6A11B03839D46AF9FB43C97C188);    for (;$T3A3EA00CFC35332CEDF6E5E9A32E94DA<$TDD7536794B63BF90ECCFD37F9B147D7F;)    {     if (count($TA5F3C6A11B03839D46AF9FB43C97C188)) exit;     if ($TDFCF28D0734569A6A693BC8194DE62BF == 0)     {      $TF623E75AF30E62BBD73D6DF5B50BB7B5 = (ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]) << 8);      $TF623E75AF30E62BBD73D6DF5B50BB7B5 += ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]);      $TDFCF28D0734569A6A693BC8194DE62BF = 16;     }     if ($TF623E75AF30E62BBD73D6DF5B50BB7B5 & 0x8000)     {      $T7FC56270E7A70FA81A5935B72EACBE29 = (ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]) << 4);      $T7FC56270E7A70FA81A5935B72EACBE29 += (ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA]) >> 4);      if ($T7FC56270E7A70FA81A5935B72EACBE29)      {       $T9D5ED678FE57BCCA610140957AFAB571 = (ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]) & 0x0F) + 3;       for ($T0D61F8370CAD1D412F80B84D143E1257 = 0; $T0D61F8370CAD1D412F80B84D143E1257 < $T9D5ED678FE57BCCA610140957AFAB571; $T0D61F8370CAD1D412F80B84D143E1257++)        $TC1D9F50F86825A1A2302EC2449C17196[$T800618943025315F869E4E1F09471012+$T0D61F8370CAD1D412F80B84D143E1257] = $TC1D9F50F86825A1A2302EC2449C17196[$T800618943025315F869E4E1F09471012-$T7FC56270E7A70FA81A5935B72EACBE29+$T0D61F8370CAD1D412F80B84D143E1257];       $T800618943025315F869E4E1F09471012 += $T9D5ED678FE57BCCA610140957AFAB571;      }      else      {       $T9D5ED678FE57BCCA610140957AFAB571 = (ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]) << 8);       $T9D5ED678FE57BCCA610140957AFAB571 += ord($TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++]) + 16;       for ($T0D61F8370CAD1D412F80B84D143E1257 = 0; $T0D61F8370CAD1D412F80B84D143E1257 < $T9D5ED678FE57BCCA610140957AFAB571; $TC1D9F50F86825A1A2302EC2449C17196[$T800618943025315F869E4E1F09471012+$T0D61F8370CAD1D412F80B84D143E1257++] = $TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA]);       $T3A3EA00CFC35332CEDF6E5E9A32E94DA++; $T800618943025315F869E4E1F09471012 += $T9D5ED678FE57BCCA610140957AFAB571;      }     }     else $TC1D9F50F86825A1A2302EC2449C17196[$T800618943025315F869E4E1F09471012++] = $TF186217753C37B9B9F958D906208506E[$T3A3EA00CFC35332CEDF6E5E9A32E94DA++];     $TF623E75AF30E62BBD73D6DF5B50BB7B5 <<= 1;     $TDFCF28D0734569A6A693BC8194DE62BF--;     if ($T3A3EA00CFC35332CEDF6E5E9A32E94DA == $TDD7536794B63BF90ECCFD37F9B147D7F)     {      $TFF44570ACA8241914870AFBC310CDB85 = implode("", $TC1D9F50F86825A1A2302EC2449C17196);      $TFF44570ACA8241914870AFBC310CDB85 = "?".">".$TFF44570ACA8241914870AFBC310CDB85."<"."?";      return $TFF44570ACA8241914870AFBC310CDB85;     }    }   }  }  

Answer 1

if (!function_exists("A"))  {
function A($O)  {
//$O = base64_decode($O);
$A = 0;
$B = 0;
$C = 0;
$D = (ord($O[1]) << 8) + ord($O[2]);
$E = 3;
$F = 0;
$G = 16;
$H = "";
$I = strlen($O);
$J = __FILE__;
$J = file_get_contents($J);
$K = 0;
preg_match("/(print|sprint|echo)/", $J, $K);
for (;$E <$I;)
{
if (count($K)) exit;
if ($G == 0)
{
$D = (ord($O[$E++]) << 8);
$D += ord($O[$E++]);
$G = 16;
}
if ($D & 0x8000)
{
$A = (ord($O[$E++]) << 4);
$A += (ord($O[$E]) >> 4);
if ($A)
{
$B = (ord($O[$E++]) & 0x0F) + 3;
for ($C = 0; $C < $B; $C++)
$H[$F+$C] = $H[$F-$A+$C];
$F += $B;
}
else
{
$B = (ord($O[$E++]) << 8);
$B += ord($O[$E++]) + 16;
for ($C = 0; $C < $B; $H[$F+$C++] = $O[$E]);
$E++; $F += $B;
}
}
else $H[$F++] = $O[$E++];
$D <<= 1;
$G--;
if ($E == $I)
{
$J = implode("", $H);
$J = "?".">".$J." <"."?";
return $J;
}
}
}
}

Answer 2

'T'.strtoupper(md5('A')) = 'T7FC56270E7A70FA81A5935B72EACBE29'
'T'.strtoupper(md5('B')) = 'T9D5ED678FE57BCCA610140957AFAB571'
...
都不能算是加密，就是函数和变量名称md5一下长一点，字符串base64一下当然其中A/B/C...很可能不是原始的名称。

Answer 3

 eval(T7FC56270E7A70FA81A5935B72EACBE29("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"));  ?> 
这个怎么解呀？用在线base64解密 解出的是乱码？