这段代码是怎么加密的？

Question

<?php
eval(base64_decode('JElJSUlJSUlJSUkxMT0nZmNsb3NlJzskSUlJSUlJSUlJSTFsPSdmd3JpdGUnOyRJSUlJSUlJbEkxbGw9J2NobW9kJzskSUlJSUlJSUlJSTFJPSdmb3Blbic7JElJSUlJSUlsbEkxMT0nb2JfZ2V0X2ZsdXNoJzskSUlJSUlJSWxJMWwxPSdwcmVnX21hdGNoX2FsbCc7JElJSUlJSUlJMWxsST0ndGltZSc7JElJSUlJSUlsSTFsST0nZmlsZW10aW1lJzskSUlJSUlJSWxJbDFsPSdvYl9zdGFydCc7'));$OOO0O0O00=__FILE__;$OOO000000=urldecode('%74%68%36%73%62%65%68%71%6c%61%34%63%6f%5f%73%61%64%66%70%6e%72');$OO00O0000=2756;$OOO0000O0=$OOO000000{4}.$OOO000000{9}.$OOO000000{3}.$OOO000000{5};$OOO0000O0.=$OOO000000{2}.$OOO000000{10}.$OOO000000{13}.$OOO000000{16};$OOO0000O0.=$OOO0000O0{3}.$OOO000000{11}.$OOO000000{12}.$OOO0000O0{7}.$OOO000000{5};$O0O0000O0='OOO0000O0';eval(($$O0O0000O0('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')));return;?>

Answer 1

后面还有这段：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

Answer 2

base64_decode urldecode 都不是加密 编码而已