Hi Stephan, On Thu, Jul 13, 2017 at 04:54:55PM +0200, Stephan Müller wrote: > Am Mittwoch, 12. Juli 2017, 23:00:32 CEST schrieb Eric Biggers: > > Hi Herbert, > > This patch adds a second KDF to the kernel -- the first is found in the keys > subsystem. > > The next KDF that may come in is in the TLS scope. > > Would it make sense to warm up the KDF patches adding generic KDF support to > the kernel crypto API that I supplied some time ago? The advantages would be > to have one location of KDF implementations and the benefit of the testmgr. > That may be a good idea. Looking at the old thread, I share Herbert's concern (http://www.spinics.net/lists/linux-crypto/msg21231.html) about there likely not being more than one implementation of each KDF algorithm. So, perhaps some simple helper functions would be more appropriate. However, making the KDFs be covered by self-tests would be very nice. Also, it seems your patch (http://www.spinics.net/lists/linux-crypto/msg21137.html) doesn't allow a salt to be passed in. In order to fully support HKDF, crypto_rng_reset() (which as I understand would be the way to invoke the "extract" step) would somehow need to accept both the input keying material and salt, both of which are arbitrary length binary. Eric
