gcry_pk_genkey with given random seed

[Moritz Schulte]

Joachim Breitner <mail@joachim-breitner.de> writes:

Hi,

> for some wired idea I have I basically need to create a RSA keypair
> from a given random seed (a MPI), and it should always output the
> same keypair for the same seed. Ideally in a well-documented way in
> case someone else needs to reimplement it.

Hmm.  Of course it is `theoretically' possible, since this problem can
be narrowed down to the question `How many changes are needed to make
this easy?'. :)

libgcrypt manages a `pool' of random data.  If this pool is empty, a
`random gathering' function is called, which then adds more random
data to the pool.  For a situation like yours it might indeed make
sense to offer the possibility to the user to control the content of
this pool.

An interface would be be needed, which can be used to install a
user-provided random gathering functions.  This way the task of
providing random bytes would be yours.

Does this idea make sense and is it worth implementing it?

		moritz
-- 
((gpg-key-id . "6F984199")
 (email      . "moritz@duesseldorf.ccc.de")
 (webpage    . "http://duesseldorf.ccc.de/~moritz/"))