[Sls-sea-dls] Key Verification using CRC

Tue Apr 19 09:31:21 UTC 2016

Following Daniel's and Craig's e-mails, I agree with Bruno's proposal.

Kind regards,

Ignacio

(Embedded image moved to file: pic19718.jpg)

Ignacio Aguilar Sánchez
Communication Systems Engineer
Electrical Engineering Department

European Space Research and Technology Centre
Keplerlaan 1, PO Box 299, 2200 AG Noordwijk, The Netherlands
Tel. (31) 71 565 5695
Fax (31) 71 565 5418
Email: ignacio.aguilar.sanchez at esa.int
www.esa.int

From:       "Moury Gilles" <Gilles.Moury at cnes.fr>
To:         "Weiss, Howard" <Howard.Weiss at parsons.com>, "Saba Bruno"
            <Bruno.Saba at cnes.fr>, "Daniel.Fischer at esa.int"
            <Daniel.Fischer at esa.int>, "sls-sea-dls at mailman.ccsds.org"
            <sls-sea-dls at mailman.ccsds.org>
Date:       19/04/2016 10:47
Subject:    RE: [Sls-sea-dls] Key Verification using CRC
Sent by:    sls-sea-dls-bounces at mailman.ccsds.org

Shall we adopt Bruno’s proposal ? In that case, we probably do not need the
challenge-response transaction.

Gilles

Gilles MOURY
CNES Toulouse
De : sls-sea-dls-bounces at mailman.ccsds.org [
mailto:sls-sea-dls-bounces at mailman.ccsds.org] De la part de Weiss, Howard
Envoyé : lundi 18 avril 2016 19:27
À : Saba Bruno; Daniel.Fischer at esa.int; sls-sea-dls at mailman.ccsds.org
Objet : RE: [Sls-sea-dls] Key Verification using CRC

I agree with Bruno.

Howie

Howard Weiss
Technical Director

PARSONS
7110 Samuel Morse Drive
Columbia, MD 21046
443-430-8089 (office)
410-262-1479 (cell)
443-430-8238 (fax)
howard.weiss at parsons.com
www.parsons.com

Please consider the environment before printing this message

From: sls-sea-dls-bounces at mailman.ccsds.org
[sls-sea-dls-bounces at mailman.ccsds.org] on behalf of Saba Bruno
[Bruno.Saba at cnes.fr]
Sent: Monday, April 18, 2016 9:48 AM
To: Daniel.Fischer at esa.int; sls-sea-dls at mailman.ccsds.org
Subject: RE: [Sls-sea-dls] Key Verification using CRC
Dear all,

One solution to avoid the use of a challenge-response system and stay with
the simple CRC for on-board key checking is to compute the CRC on BOTH the
Key-ID and the key itself.

Ideally, what we know as a “key” would be a “Meta-Key”, comprising :

      -          The Key ID, unique identifier of the key for the whole
      mission duration,
      -          The Key itself (secret random data)
      -          The CRC, computed on the Key ID and the key itself.

This “Meta-Key” should be considered as an single entity, not splittable,
being stored, transferred and distributed as is (on-board AND at ground
level, from generation to destruction).

Cheers,

Bruno Saba
CNES
DCT/TV/IN
18 Avenue Edouard Belin
31401 TOULOUSE Cedex 9
Tel : + 33 (0) 5 61 28 28 76
Fax : + 33 (0) 5 61 28 19 96

De : sls-sea-dls-bounces at mailman.ccsds.org [
mailto:sls-sea-dls-bounces at mailman.ccsds.org] De la part de
Daniel.Fischer at esa.int
Envoyé : dimanche 17 avril 2016 13:13
À : sls-sea-dls at mailman.ccsds.org
Objet : [Sls-sea-dls] Key Verification using CRC

Dear all,

I was discussing our new approach to key verification using the
onboard-stored CRCs with David,

He came up with a keen observation.

The CRC-based key verification is somewhat weaker than one based on a
challenge-response. The reason is that the CRC ensues you that the key at a
certain slot is still OK in terms of integrity. In contrast to the
challenge-response approach it DOES NOT tell you that the key is the same as
the key with same key ID on ground.

Is this an issue for us? What do you think? The only way we have to check key
synchronisation is to use a key for actual traffic protection and see if it
works.

What do you think?

Cheers
Daniel

Dr. Daniel Fischer
----------------------------
Data Systems Manager
Ground Segment Engineering Support Office (OPS-GE)
Ground Systems Engineering Department
Directorate of Operations

European Space Agency - ESOC
Robert-Bosch-Str. 5
D-64293 Darmstadt - Germany
Tel: +49 (0) 6151 90 2718 - Fax: +49 (0) 6151 90 2718
Web: http://www.esa.int[esa.int]
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