Hex-Oct DecoderConverts an octal and hexadecimal escape sequence to a string.
Combinations of characters consisting of a backslash ( \ ) followed by a letter or set of numbers are called escape sequences. To represent a newline, single quote, or some other characters in a character constant, you must use escape sequences. The Escape sequence is treated as a single character and is therefore a valid character constant.
You've probably seen a line like $_SERVER["\x44\117\x43\125\115\x45\116\x54\x5f\x52\x4f\117\124"] in code, but you didn't understand what was hidden behind it set of characters. This is a fairly commonly used way to hide malicious code, this line is identical to $_SERVER["DOCUMENT_ROOT"]. With the help of Hex-Oct decoder, you can easily convert such expressions into human-readable code.