FastMail.FM patchset - new patches
David Carter
dpc22 at cam.ac.uk
Thu Mar 15 08:09:04 EST 2007
On Thu, 15 Mar 2007, Rob Mueller wrote:
> May not be true, but:
>
>> Is it safe? - we calulated that with one billion messages you have a one
>> in 1 billion chance of a birthday collision (two random messages with
>> the same UUID).
>
> Is true.
Fair enough.
With hindsight I should probably have defined message UUIDs to be the full
MD5 hash: 128 bits isn't that much worse than 96 bits per message. What is
the CPU overhead like for calculating MD5 sums for everything on the fly?
UUIDs started out life as Mailbox UniqueID (64 bits) plus Message UID (32
bits), hence the size and rather unfortunate name. The hash algorithmn
used to generate mailbox uniqueIDs is a bit basic, which is why I switched
to generating them on the fly from master.
--
David Carter Email: David.Carter at ucs.cam.ac.uk
University Computing Service, Phone: (01223) 334502
New Museums Site, Pembroke Street, Fax: (01223) 334679
Cambridge UK. CB2 3QH.
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