Re: Question about ahash export and import

Le 27/09/2017 à 11:08, Herbert Xu a écrit :

On Tue, Sep 26, 2017 at 01:09:05PM +0200, Kamil Konieczny wrote:

quoted

Can import() be called without _any_ init(), for example
after reboot of machine ? Is following scenario valid:

Of course it can.  import must restore the state of the request
to that at the time when export was called.

import does not need to be called after init.  init simply resets
the hash state for new update/final calls.

quoted

init(), update() 0 or more times, export(),
save exported data to pernament storage
reboot machine
load crypto driver, import() saved state ?

Yes this must be supported.

Basically after any update call is complete (you've called the
completion function), you should be able to call export and
completely extract the partial (as opposed to finalised) hash
state.

Can we consider that once an export has been done, no new update call will be performed prior to doing an init or an import ? Or should it be possible to continue with an update or a final/finup call after an export ?

Remember we need to support an arbitrarily large number of
concurrent hashing operations.  So you cannot keep a hash state
in hardware indefinitely just because the user has not called
finalize on it.

Cheers,

Christophe