Subject: Authentication field in LSPs

From: Radia Perlman - Boston Center for Networking <[email-masked]>
Date: Sat, 1 May 1999 15:22:30 -0400 (EDT)

The cleartext password authentication allowed for a set of receive passwords and 
a single transmit password, which allows migration from one secret to another.

I didn't see any mention of the possibility of multiple receive passwords in
the HMAC internet draft. Is it allowed? If not, it seems like it would be
difficult to ever change either the per-link secret or the area-wide
secret.

I think there's two ways of supporting multiple receive passwords, in the
same spirit as the cleartest password. One is to simply allow multiple of
them, and have to compute the HMAC according to all of them, and accept
it if any of them match. Given that you're unlikely to need more
than 2, this doesn't seem too bad.

The other solution would be to include a "key ID" field in the authentication
option which would tell you which of the receive secrets to use in the HMAC
calculation.

Radia

---

From: Tony Li <[email-masked]>
Date: Sat, 1 May 1999 15:14:10 -0700 (PDT)

There will be a key id field.

Tony

|  From: Radia Perlman - Boston Center for Networking <[email-masked]>
|  Reply-To: Radia Perlman - Boston Center for Networking <[email-masked]>
|  Content-MD5: plssV7LdXBZOYqs3TZ44qA==
|  
|  
|  The cleartext password authentication allowed for a set of receive passwords and 
|  a single transmit password, which allows migration from one secret to another.
|  
|  I didn't see any mention of the possibility of multiple receive passwords in
|  the HMAC internet draft. Is it allowed? If not, it seems like it would be
|  difficult to ever change either the per-link secret or the area-wide
|  secret.
|  
|  I think there's two ways of supporting multiple receive passwords, in the
|  same spirit as the cleartest password. One is to simply allow multiple of
|  them, and have to compute the HMAC according to all of them, and accept
|  it if any of them match. Given that you're unlikely to need more
|  than 2, this doesn't seem too bad.
|  
|  The other solution would be to include a "key ID" field in the authentication
|  option which would tell you which of the receive secrets to use in the HMAC
|  calculation.
|  
|  Radia
|  
|

---

From: [email-masked] (Randall Atkinson)
Date: Thu, 13 May 1999 19:40:53 -0700

On May 1 15:22, Radia Perlman - Boston Center for Networking wrote:
} Subject: Authentication field in LSPs

% The cleartext password authentication allowed for a set of receive
% passwords and a single transmit password, which allows migration from
% one secret to another.

	The right way to handle key rollover is with a Key-ID.  This was
the crux of my comments at last IETF ISIS mtg.  My understanding is that
Key-ID is coming -- to reward my insistence I think I now owe tli
proposed
text.  Allowing multiple keys without a Key-ID is a bad idea when
cryptography is in use.

	In the mean time, folks can look at Keyed-MD5 for OSPF/RIPv2 for
something more about my approach.

Ran