[p2p-hackers] convergent encryption reconsidered

[Ivan Krstić]

On Mar 20, 2008, at 3:42 PM, zooko wrote:
>    They extended the confirmation-of-a-file attack into the
>    learn-partial-information attack. In this new attack, the
>    attacker learns some information from the file. This is done by
>    trying possible values for unknown parts of a file and then
>    checking whether the result matches the observed ciphertext.

How is this conceptually different from classic dictionary attacks,  
and why does e.g. running the file through PBKDF2 and using the result  
for convergence not address your concern(s)?

--
Ivan Krstić <krstic at solarsail.hcs.harvard.edu> | http://radian.org

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