[tahoe-dev] "Elk Point" design for mutable, add-only, and immutable files
zooko at zooko.com
Sat Oct 10 22:42:08 UTC 2009
I've started a matrix of ways that an immutable file cap format could
Unfortunately I can't conveniently replicate the data into an email
message (except by sending HTML-formatted email, which I assume most
of you would hate and which I don't even know how to do).
So go read this page! http://allmydata.org/trac/tahoe/wiki/NewCaps/
It includes how expensive it is to brute-force each part, which show
us how big the crypto values R and T need to be.
Also pay attention to the "what crypto property do we rely on"
column. I wouldn't be surprised if SHA-256's collision-resistance is
increasingly called into question in future years. (On the other
hand I would be rather shocked if SHA-256's second-pre-image
resistance were called into question in the forseeable future.)
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