From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 5 Mar 2008 06:52:55 +0100 From: Enrico Weigelt To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: Re: [9fans] thoughs about venti+fossil Message-ID: <20080305055255.GA4575@nibiru.local> References: <20080305040019.GA13663@nibiru.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Topicbox-Message-UUID: 6f1625e2-ead3-11e9-9d60-3106f5b1d025 * Roman Shaposhnik wrote: > On Mar 4, 2008, at 8:00 PM, Enrico Weigelt wrote: > >some thoughts about venti that go around in my mind: > > > >1. how stable is the keying ? sha-1 has only 160 bits, while > > data blocks may be up to 56k long. so, the mapping is only > > unique into one direction (not one-to-one). how can we be > > *really sure*, that - even on very large storages (TB or > > even PB) - data to each key is alway (one-to-one) unique ? > > http://www.nmt.edu/~val/review/hash/index.html Tells me what I already suspected: compare-by-hash can be an dangerous game (even if very uncertain). So I wouldn't count current venti secure and stable if one storage is large and used for a long time. cu -- --------------------------------------------------------------------- Enrico Weigelt == metux IT service - http://www.metux.de/ --------------------------------------------------------------------- Please visit the OpenSource QM Taskforce: http://wiki.metux.de/public/OpenSource_QM_Taskforce Patches / Fixes for a lot dozens of packages in dozens of versions: http://patches.metux.de/ ---------------------------------------------------------------------