[Sls-sea-dls] Key Verification using CRC

[Daniel.Fischer at esa.int]

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
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