RE: [vhdl-200x] Protect tool - Key block clarification

From: Peter Ashenden <peter_at_.....>
Date: Sun Jul 15 2007 - 23:20:12 PDT

Thanks for raising this issue. It was a detail I was not aware of when we
drafted the specification. The LRM is silent on how the initialization
vector should be determined, but the interpretation you suggest makes sense
for digital envelopes.

As for encryption using symmetric cipers with secret keys (not using digital
envelopes), the secret key is not included in the decryption envelope. It is
assumed the recipient of the model has access to the key in their keystore.
That begs the question of what initialization vector is to be used. If we
don't specify how the encryption tool generates an IV, the decryption tool
won't be able to decrypt. Any suggestions?

Please note that the above is my personal input, not the response of the
working group. I'll raise an issue report for the Accellera VHDL-TC on this
issue so that we can formalize a response.



Dr. Peter J. Ashenden
Ashenden Designs Pty. Ltd.
PO Box 640                    VoIP: sip://
Stirling, SA 5152             Phone: +61 8 7127 0078
Australia                     Mobile: +61 414 70 9106

> -----Original Message-----
> From: 
> [] On Behalf Of Michael Smith
> Sent: Saturday, 14 July 2007 9:31 AM
> To:
> Subject: [vhdl-200x] Protect tool - Key block clarification
> I'm in the process of implementing the protect tool 
> directives described in the draft IEEE P1076-2006, section 
> 22. I was looking for a clarification on the key 
> specification/key block (sections and
> All symmetric encryption methods described in section 
> use Cypher-Block-Chaining, which requires an initial 
> vector (IV) to start the chain. My interpretation is that the 
> encoded and encrypted text of the key block must contain both 
> the encryption key and the initial vector, in that order with 
> no space separating them. The format the key and IV appear in 
> is important for ensuring compatibility between different 
> applications. Is this interpretation correct?
> -----------------------
> Michael Smith
> R&D Engineer, SaberHDL
> Synopsys Inc.
> -----------------------
> -- 
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Received on Sun Jul 15 23:20:30 2007

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