Re: encryption program question

On 2012-02-28 18:41, John Elliot wrote:
> Anyway, I've never heard anything about keys needing to be a prime
> number of digits long and from what I understand such a requirement
> wouldn't make any sense at all.

Just to explain that a little more. If you only used keys that were
prime digits long you'd be pretty seriously constraining your keyspace
so the only thing you'd be really doing is making your system less
secure by knocking out a large swathe of potential keys.

I've also heard, although I don't remember where or why, that it's not
considered good practice to use a key longer than the maximum key size.
I think usually ciphers just wrap to apply the extra data in longer keys
and I've heard there is a minor concern about the fact that happens.
Sorry to be vague but I didn't pay much attention to the detail I just
took away "don't use keys longer than the supported key length."