SFS for anonymity

[Peter Fairbrother]

Given: an online Steganographic Filing System database based on the second
construction of Anderson, Needham and Shamir*, with many users. Users write
email to the data base, with random cover writes. They read from the
database to collect their mail, reads are covered by random cover reads, and
random reads/writes when they have no mail.

Assumptions include: Messages are encrypted. Users would prefer to lose
their mail than have it compromised. All communications and alterations to
the database are intercepted, and the database itself is compromised. Shared
secret keys between users are allowed. Stored hashes of the database state
are allowed, to ensure that it has changed enough. The database/userbase can
be split into groupwrite/anyread and anywrite/groupread segments (group
membership is random and not secret).

The point is to foil traffic analysis without a distributed network or
trusted third party. Any ideas/insuperable objections?

(Could datarates be optimised to implement untraceable internet telephony as
well as email on a DSL/cable-type connection?)

Comments? 


-- Peter

* http://www.ftp.cl.cam.ac.uk/ftp/users/rja14/sfs3.ps.gz




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