Re: [hybi] deflate-stream and masking
"Bob Gezelter" <gezelter@rlgsc.com> Mon, 20 June 2011 14:09 UTC
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From: "Bob Gezelter" <gezelter@rlgsc.com>
To: hybi@ietf.org
Date: Mon, 20 Jun 2011 07:09:15 -0700
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Subject: Re: [hybi] deflate-stream and masking
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As I have noted before, Greg's observation about the interaction of masking and compression is undoubtedly correct. To be effective, compression must be done when the steam of data is most strongly correlated. In short, this should be BEFORE multiplexing, encryption, and masking. Data on different multiplexed streams cannot be assumed to be correlated, and correlation is needed for effective compression. Encrypting or masking data to create randomness similarly negates the effectiveness of compression. When dealing with correlated data (e.g., the contents of a printable file, or even a PostScript file), I have seen compression factors of 100:1. If the data had first been encrypted, or randomly masked, the ratio would have been likely 2:1 (what is often achieved by disk or tape compression facilities), or even less than 1:1 (worst case). Compression should be done within each sub-stream (assuming multiplexing, which is not in the current specification), and in any event, before encryption and masking. - Bob Gezelter, http://www.rlgsc.com
- [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Dirkjan Ochtman
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Bob Gezelter
- Re: [hybi] deflate-stream and masking Arman Djusupov
- Re: [hybi] deflate-stream and masking Bruce Atherton
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Ian Fette (イアンフェッティ)
- Re: [hybi] deflate-stream and masking Andy Green (林安廸)
- Re: [hybi] deflate-stream and masking Bruce Atherton
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Brian
- Re: [hybi] deflate-stream and masking Arman Djusupov
- Re: [hybi] deflate-stream and masking Philipp Serafin
- [hybi] Fwd: Re: deflate-stream and masking Justin Lee
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Alexander Philippou
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Patrick McManus
- Re: [hybi] deflate-stream and masking Alexander Philippou
- Re: [hybi] deflate-stream and masking Peter Saint-Andre
- Re: [hybi] deflate-stream and masking Gabriel Montenegro
- Re: [hybi] deflate-stream and masking Patrick McManus
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Willy Tarreau
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking David Endicott
- Re: [hybi] deflate-stream and masking Peter Saint-Andre
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking John Tamplin
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Bjoern Hoehrmann
- Re: [hybi] deflate-stream and masking Greg Wilkins
- Re: [hybi] deflate-stream and masking Peter Saint-Andre