Replace common text with hex digits
<p>I have the user typing a string of 32 characters which are supposed to be hex digits.
But it would be nice if the program "auto-fixes" the string instead preventing him typing values outside of the hex digits with RegeX. 
For example if user typed O that would be converted to 0 , or maybe even 8 to B
I know that the last pair both belong to hex values, but they are easily confused between each other.</p>

<p>On a side note, the program can check if the string is correct but only once you type it correct, consider it like a password, so trying 2 or 3 strings to see if they are correct it's no problem, checking all combinations is ;)</p>

<p>Thanks for every answer.</p>
