Creativity and security

brucee at chunder.com brucee at chunder.com
Mon Mar 27 15:41:23 EST 2006


regardingg the XXXing on receipts it turns out that things aren't
as grim as i thought.  i anlayzed the checksum algorithm and if
you are missing n digits there are 10^(n-1) clashes.

i verified this with a brute force program.

but in the "photograph the card" scenario ... if one digit is
blurry then you still win because 10^(n-1) is 1.

if two are unknown then mr nasty could try buying stuff from
10 diferent sites.

brucee

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at metzdowd.com



More information about the cryptography mailing list