php string functions - Robuta Search

https://www.codecademy.com/resources/docs/php/string-functions/hex2bin

Converts a string of hexadecimal values to its binary representation.

https://www.php.net/manual/en/taint.detail.basic.php

Functions and Statements which will spread the tainted mark of a tainted string

https://www.codecademy.com/resources/docs/php/string-functions/ord

Returns an integer between 0 and 255 corresponding to the binary value of the first character of a string.

https://www.codecademy.com/resources/docs/php/string-functions/trim

Strips whitespace and/or other characters from the beginning and end of a string.

https://www.codecademy.com/resources/docs/php/string-functions/str-replace

Returns a string with occurrences of a specified substring replaced by another string.