Re: [Qemu-devel] [PATCH v2 4/7] crypto: use correct derived key size when timing pbkdf

[Eric Blake]

On 09/12/2016 09:13 AM, Daniel P. Berrange wrote:
> Currently when timing the pbkdf algorithm a fixed key
> size of 32 bytes is used. This results in inaccurate
> timings for certain hashes depending on their digest
> size. For example when using sha1 with aes-256, this
> causes us to measure time for the master key digest
> doing 2 sha1 operations per iteration, instead of 1.
> 
> Instead we should pass in the desired key size to the
> timing routine that matches the key size that will be
> used for real later.
> 
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
>  crypto/block-luks.c       |  2 ++
>  crypto/pbkdf.c            | 10 +++++++---
>  include/crypto/pbkdf.h    |  6 +++++-
>  tests/test-crypto-pbkdf.c |  1 +
>  4 files changed, 15 insertions(+), 4 deletions(-)
> 

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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