[EMAIL PROTECTED] wrote:
>
> ... If you enter the wrong digit or transpose digits they won't
> match.
>
Welllll.... Actually, it's MUCH weaker than that. It won't detect
any of the following transpositions:
05 <-> 50
16 <-> 61
27 <-> 72
38 <-> 83
49 <-> 94
In other words, there's about an 89% probability that transposing
adjacent arbitrary digits in the base number will get caught, and
about an 11% probability that it will be missed (the check digit
will still match).
>
> It will also reject almost all made up numbers for the same
> reason.
>
This is also WAY overstated. Because it is a mod 10 system,
there is a 90% probability that a completely random number will
be caught as bogus, and a 10% probability that it will be
accepted as valid.
-jn-
