Re: allocation of key material into keys

Lewis McCarthy <lmccarth@cs.umass.edu> Mon, 28 October 1996 23:25 UTC

Message-ID: <32753724.3F54@cs.umass.edu>
Date: Mon, 28 Oct 1996 17:43:48 -0500
From: Lewis McCarthy <lmccarth@cs.umass.edu>
Organization: Theoretical Computer Science Group, UMass-Amherst
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Subject: Re: allocation of key material into keys
References: <199610282029.PAA03172@thunk.orchard.medford.ma.us>
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Bill Sommerfeld writes:
> Here's a rephrase which I think is more precise.  Let me know if this
> is not what you intended..
> 
>     I'd like to propose that the key management protocol
>     specifications only be responsible for generating a "blob" of
>     key material at least N bits long containing at least K bits of
>     entropy.  For obvious reasons, K <= N.
[...]

At the risk of stating the obvious, the K bits of entropy should
presumably be ~ evenly distributed among the N bits of VPIblob, i.e.
padding K bits from a physical random source with 0s to reach N bits
would be unacceptable. Otherwise a transform might grab a hunk of
padding and use it as key material....

-Lewis	<mailto:lmccarth@cs.umass.edu>

Re: allocation of key material into keys Lewis McCarthy