[quicwg/base-drafts] The packet number gap is overspecified (#1034)
Christian Huitema <notifications@github.com> Sat, 30 December 2017 20:22 UTC
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Date: Sat, 30 Dec 2017 20:22:16 +0000
From: Christian Huitema <notifications@github.com>
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Subject: [quicwg/base-drafts] The packet number gap is overspecified (#1034)
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The "Packet Number Gap" is currently specified in section 7.7.1.1 of the transport draft. The section correctly states that "In order to avoid linkage, the packet number gap MUST be externally indistinguishable from random." But then, it goes on to present a cryptographic formula:
~~~
Gap = HKDF-Expand-Label(packet_number_secret,
"QUIC packet sequence gap", sequence, 4)
~~~
The formula relies on a "packet number secret" derived from the master secret.
This seems seriously over specified. What is exactly the reason to use this derivation, rather than merely drawing a 32 bit random number? Why the complexity of another call to the crypto library, and another secret to maintain in the connection context? Do we expect the receiving end of the connection to verify that the gap has been computed using the proper secret?
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https://github.com/quicwg/base-drafts/issues/1034
- [quicwg/base-drafts] The packet number gap is ove… Christian Huitema
- Re: [quicwg/base-drafts] The packet number gap is… Christian Huitema
- Re: [quicwg/base-drafts] The packet number gap is… Christian Huitema
- Re: [quicwg/base-drafts] The packet number gap sp… ianswett
- Re: [quicwg/base-drafts] The packet number gap sp… Martin Thomson