Re: [TLS] New Cached info draft

"Kemp, David P." <> Thu, 25 March 2010 16:14 UTC

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Date: Thu, 25 Mar 2010 12:14:13 -0400
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From: "Kemp, David P." <>
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Subject: Re: [TLS] New Cached info draft
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While I completely support the use of a non-cryptographic hash function
for this application, it is interesting to note how NIST guidance has
been misinterpreted by the CMVP labs.


Elaine Barker, speaking on algorithm evolution at a security conference
this week, stated that there are no restrictions on using SHA-1 for
purposes other than generating digital signatures for the foreseeable
n-paper.pdf states that SHA-1 is "Approved for all non-digital signature
applications (including digital signature verification, HMACs, KDFs,
RNGs, ...)" for new validations and for use of existing validated
products beyond 2010.





From: [] On Behalf Of
Stefan Santesson
Sent: Thursday, March 25, 2010 10:56 AM
Subject: [TLS] New Cached info draft



I have now collected all suggestions and agreements reached in the
cached info discussion and made a substantial re-write of the current
hed-info-04.txt> &url2=draft-ietf-tls-cached-info-04.txt

Major changes:
- The 64 bit FNV-1 non-cryptographic hash is used to provide a digest
over cached data. All use of hash algorithms has been removed, so also
all elements of hash algorithm agility. The FNV-1 digest algorithm used
in this specification is defined in Annex A.

- It is now possible to query a server with an empty cached info
extension to find out if, and to what extent the server supports caching
before the client starts to cache data for that server.

- The data substitution syntax has been explicitly defined for both
defined object types

I will present the proposed changes at the TLS meeting today.