Greetings,
* Stephen Frost (sfrost@snowman.net) wrote:
> * Robert Haas (robertmhaas@gmail.com) wrote:
> > Another idea might be - instead of doing nonce++ every time we write
> > the page, do nonce=random(). That's eventually going to repeat a
> > value, but it's extremely likely to take a *super* long time if there
> > are enough bits. A potentially rather large problem, though, is that
> > generating random numbers in large quantities isn't very cheap.
>
> There's specific discussion about how to choose a nonce in NIST
> publications and using a properly random one that's large enough is
> one accepted approach, though my recollection was that the preference
> was to use an incrementing guaranteed-unique nonce and using a random
> one was more of a "if you can't coordinate using an incrementing one
> then you can do this". I can try to hunt for the specifics on that
> though.
Disucssion of generating IVs here:
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
section 8.2 specifically.
Note that 8.3 also discusses subsequent limitations which one should
follow when using a random nonce, to reduce the chances of a collision.
Thanks,
Stephen