40 lines
1.1 KiB
PHP
40 lines
1.1 KiB
PHP
<?php
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function getObfuscationSalt(){
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$saltFile=dirname(__FILE__)."/idObfuscation_salt.php";
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if(file_exists($saltFile)){
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require $saltFile;
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}else{
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$bytes=openssl_random_pseudo_bytes(4);
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$sf=fopen($saltFile,"w");
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fwrite($sf,chr(60)."?php\n");
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fwrite($sf,'$OBFUSCATION_SALT=0x'.bin2hex($bytes).";\n");
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fwrite($sf,"?".chr(62));
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fclose($sf);
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require $saltFile;
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}
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return isset($OBFUSCATION_SALT)?$OBFUSCATION_SALT:0;
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}
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/*
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This is a simple reversible hash function I made for encoding and decoding test IDs.
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It is not cryptographically secure, don't use it to hash passwords or something!
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*/
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function obfdeobf($id){
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$salt=getObfuscationSalt()&0xFFFFFFFF;
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$id=$id&0xFFFFFFFF;
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for($i=0;$i<16;$i++){
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$id=$id^$salt;
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$salt=(($salt>>1)&0xFFFFFFFF)|(($salt&0x00000001)<<31);
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$id=((0x0000FFFF&$id)<<16)|((0xFFFF0000&$id)>>16);
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$id=(($id>>1)&0xFFFFFFFF)|(($id&0x00000001)<<31);
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}
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return $id;
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}
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function obfuscateId($id){
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return str_pad(base_convert(obfdeobf($id+1),10,36),7,0,STR_PAD_LEFT);
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}
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function deobfuscateId($id){
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return obfdeobf(base_convert($id,36,10))-1;
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}
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//IMPORTANT: DO NOT ADD ANYTHING BELOW THE PHP CLOSING TAG, NOT EVEN EMPTY LINES!
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?>
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