Re: [dtn-security] Re: [dtn-dev] Re: SDNV-new

Rajesh Krishnan <krash@bbn.com> Tue, 31 May 2005 20:04 UTC

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From: Rajesh Krishnan <krash@bbn.com>
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Subject: Re: [dtn-security] Re: [dtn-dev] Re: SDNV-new
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Date: Tue, 31 May 2005 16:04:08 -0400 (EDT)
In-Reply-To: <429CA577.8000705@jpl.nasa.gov> from "Scott Burleigh" at May 31, 2005 10:57:11 AM
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> >I took a pass at changing the language from the original LTP spec to
> >match my new proposal for SDNV encodings:
> >  
> >
> This is really good, Mike.  What we still need to settle on is the 
> encoding scheme: 1-2-3-4-5-6-7-8, 1-2-3-4-5-6-8-16, 
> 1-2-4-8-16-32-64-128, or something else.  Anybody have any strong 
> feelings on this?

The case for byte-savings can be made primarily for small sizes such 
as 1,2, and 4.  OTOH, large numbers (say, up to 4096-bits) are useful
for encoding cryptographic keys.  

Say, how about:

1-2-4-8-16-128-256-512      (2^x bytes)
0-1-2-3-4-7-8-9             (x: integers congruent to {0 1 2 3 4} mod 7)

1-2-4-8-16-256-1024-8192    (2^x bytes)
0-1-2-3-4-8-10-14           (x: integers s.t. 3^x+2 is a prime)

1-2-4-8-16-256-512-1024     (2^x bytes)
0-1-2-3-4-8-9-10            (x: integers s.t. x is a sum of at most 4 cubes)

1-2-4-8-32-128-2048-8192    (2^x)
0-1-2-3-5-7-11-13           (x: 0, 1, then integers s.t. x is a prime )

See http://www.research.att.com/~njas/sequences/

Best Regards,
Rajesh