Subject: Comment on draft-ietf-ipngwg-addrconf-privacy-00.txt

From: "Matt Crawford" <[email-masked]>
Date: Tue, 13 Jul 1999 04:09:04 -0500

As the draft is written, if a node ever reveals its built-in
identifier and one "privacy" identifier, all subsequent
identifiers can be predicted.  If the node uses zeros to start
the sequence, then knowledge of the built-in identifier is
sufficient.

To fix: require starting with random bits, not zero, and keep
128 bits as "history", not 64.  (No new random input is then
needed to generate more identifiers.)  If stable storage is not
available aros reboots, require new rndom bits at each boot.

			Matt
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From: [email-masked]
Date: Wed, 14 Jul 1999 11:02:34 +0900

At around Tue, 13 Jul 1999 04:09:04 -0500,

> available aros reboots, require new rndom bits at each boot.

what are some ballpark figures regarding collisions of sets of (48,
64, etc.) randomly chosen bits?  applying birthday problem reasoning i
came up w/ a formula, but i haven't figured out how to solve it via
brute force w/ the numbers (too big) involved, yet -- there must be a
better way :-)

what are the flaws w/ the approach of randomly generating a mac
address and then using this to create an eui-64 based identifier as
described in appendix a of rfc 2373?  specifically, any problems other
than potential collisions?  is there a generally acceptable collision
threshold?
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