Re: [PATCH v1] crypto: driver for tegra AES hardware

[Varun Wadekar <vwadekar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

>>> why do you need to clear the entire key table if it will be
>>> overwritten anyway?
>> If you set a > 128-bit key and then set a 128-bit key, the remaining
>> bits still remain in the key table. Similarly, if we use updated IV in
>> one operation and want to use the initial IV for the next, the updated
>> IV will still remain in the key table. The entire key table is copied to
>> the AES engine. Even though, we program the engine with the exact number
>> of bits to use for the key and whether to use the updated/initial IV, I
>> feel its better if the unused bits are zero instead of having garbage.
> you're losing free performance.

I am really not comfortable having garbage in the keytable. Can you
suggest another way to ensure this?