Re: CRC Issue in Security Draft - Why Encrypted type?

[P.Pillai@Bradford.ac.uk]

Hi Sunny,

I also wanted to ask one more thing- What is the reason to have an encrypted
Type field? What do we need to protect it for?

Regards
Prashant


Quoting Christian Praehauser <cpraehaus@cosy.sbg.ac.at>:

> Hello Sunil!
>
> S.Iyengar@surrey.ac.uk wrote:
>
> >
> >1) As indicated in the ULE specs a 32 bit polynomial CRC is sued to provide
> bit errors and integrity protection. And the receiver should first check CRC
> before it gets the complete SNDU in the buffer.  But once the security
> processing is done, at the receiver side the security process should be done
> first and then handle the SNDU.
> >
> >
> The CRC also protects all extension headers, so it should be verified
> before inspecting/processing any extension headers.
> If you do not generate ULE SNDUs following the general format, you will
> get lots of ugly CRC errors at non-ULE-security-aware receivers.
>
> Repeating the question from Prashant:
> What is the reason for encrypting the whole SNDU including the CRC32?
>
> Is it a check if decryption was successful, thus avoiding to get wrong
> data up the receiver stack, e.g. if the transmitter/receiver keys are
> out of sync?
>
> Cheers,
> Christian.
>
> --
> ________________________________________
> | Christian Praehauser                  |
> |---------------------------------------|
> | Email:                                |
> |  cpraehaus@cosy.sbg.ac.at             |
> | Address:                              |
> |  Institut fuer Computerwissenschaften |
> |  Jakob-Haringer-Strasse 2             |
> |  A-5020 Salzburg, Austria             |
> |_______________________________________|
>
>


-- 
Prashant Pillai
Research Assistant
School of Engineering, Design and Technology
University of Bradford
Bradford, BD7 1DP
West Yorkshire
United Kingdom
Phone: 0044-1274-233720
email: p.pillai@bradford.ac.uk
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