Re: [PATCH] Speeding up FAT operations

Helge Hafting (helge.hafting@daldata.no)
Fri, 25 Sep 1998 09:42:51 +0100


In <19980925095215.H7297@silverand.goldweb.com.au>, on 09/25/98
at 09:52 AM, Matthew Hawkins <matt@mail.goldweb.com.au> said:

>Note that 255 isn't the only blank space character in the ASCII chart.
>There's three or four of them. I routinely ignored 255 as that was the
>one most people used, hence was easily "crackable" if somebody figured
>out that's what's you had done. 11 characters of ASCII 255's can be done
>real-time by a human in a minute or two. Now, combinations of all four
>blanks in all 11 filename characters... that was more time than I had
>unless I knew the combination. Much safer than an ATM PIN number (using
>NDD to work it out is akin to holding a gun to the head of the guy with
>the plastic card and demanding the PIN number ;)

Too easy to crack, because it can be done in one try.
No need for NDD. A simple program using findfirst("*.*") and findnext()
could get the filename, and then print out the numerical values for the 11
characters. Or you could do

DIR > listing
DEBUG listing
-d

Even dir would write out those special characters. You couldn't see the
difference because they was all blank, but debug would do the trick.

Changing the ega/vga font would also reveal such tricks instantly. Simply
edit the codepage file with a binary editor and change long sequences of
zeroes (blank characters) to something else. Oh, this is about as
advanced as using NDD, but DIR+DEBUG could be used by anybody.

Helge Hafting

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