Subject: [Ntp] New security and protocol enhancements for NTP

From: "David L. Mills" <[email-masked]>
Date: Tue, 10 Nov 2020 13:21:16 -0500

Folks,

A while back, I tossed a memo over the fence for review and discussion 
in the NTP working group. The intent was not to prolong the NTS 
discussion, but to concentrate on implementation and testing of new 
protocols and algorithms.

A new and expanded version of the memo is now available. I have included 
an abstract in this message along with three cosmic laws to consider. 
The memo can be found at

https://www.eecis.udel.edu/~mills/Autokey3.txt

Ordinarily, the memo would best be revealed as an internet draft on the 
way to an informational RFC. Your review and suggestions in this 
adventure would be delightful. The intent is not to compete with current 
proposals for exotic new features, but to suggest productive 
embellishments that improve the design and performance.

My apologies for occasional spelling and grammar errors in the document; 
I have become blind and must rely on a screen reader, which is awkward 
at best.

Dave

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From: "David L. Mills" <[email-masked]>
Date: Sat, 14 Nov 2020 16:49:25 -0500

Apologies all!   The following abstract and three cosmic laws should 
have been included with my previous message.  The full memo may be found 
here:  https://www.eecis.udel.edu/~mills/Autokey3.txt

Dave

Security and Protocol Enhancements for the Network Time Protocol (NTP)

David L. Mills, Harlan Stenn (Ed)
5 November,2020

Abstract
   
This memo explores new security and protocol enhancements for the 
network time protocol (NTP). It proposes new security schemes compatible 
with RFC5905, along with a replacement for the Autokey security scheme 
described in RFC5906.

The onwire protocols have been refined and improved. The interleave 
schemes optimize accuracy in all modes, while simplifying the design and 
configuration. The huff 'n puff filters optimize accuracy under severe 
network congestion conditions. The dynamic key agreement algorithms can 
be used in all modes except broadcast.  Individual client associations 
can be configured for nonsecure, private key secure, or public key 
secure cryptography.

The protocol and security enhancements are compatible with the current 
reference implementation and others in the community. To acknowledge its 
ancestry, the proposed design is called NTP Lite. NTP Lite is resistant 
to security attacks, protocol errors and key disclosure. It involves 
various hash, encryption, agreement and signature algorithms protecting 
NTP hosts against wiretap and middleman atrocities.

NTP Lite is based on UDP and a single port 123 shared with NTP. The 
design supports all NTP modes, including symmetric, client/server and 
broadcast modes.  The design is based on a state machine and a set of 
extension fields appended to the NTP packet header.

NTP Lite can be compiled and installed with or without NTS and the 
selected scheme activated by a configuration switch in each association. 
This allows a client to support any scheme compatible with a common 
suite of protocol exchanges.

Fundamental Axioms for NTP Lite

Law 1: A packet may not injure a peer or, through inaction, allow a peer 
to come to harm.
 
Law 2: A packet must obey orders given it by peers except where such 
orders would conflict with the First Law.

Law 3: A packet must protect its own existence as long as such 
protection does not conflict with the First or Second Law.

-- Apologies to Isaac Asimov

---

From: Tim Ruffing <[email-masked]>
Date: Mon, 16 Nov 2020 11:20:36 +0100

Hi David,

Since this is partly about cryptography, have you considered seeking
advice from the CFRG?

https://datatracker.ietf.org/rg/cfrg/about/

I expect they're willing to help and/or have a look at the
cryptographic parts in proposed NTP enhancements.

Best,
Tim

On Sat, 2020-11-14 at 16:49 -0500, David L. Mills wrote:
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