Re: [PATCH 0/2] crypto: omap-sha1-md5: OMAP3 SHA1 & MD5 driver

[Herbert Xu <herbert@gondor.apana.org.au>]

Hi:

OK so you did answer my question :)

Dmitry Kasatkin <dmitry.kasatkin@nokia.com> wrote:
>
> Interesting case with hmac.
> 
>     return crypto_shash_init(&desc.shash) ?:
>            crypto_shash_update(&desc.shash, ipad, bs) ?:
>            crypto_shash_export(&desc.shash, ipad) ?:
>            crypto_shash_init(&desc.shash) ?:
>            crypto_shash_update(&desc.shash, opad, bs) ?:
>            crypto_shash_export(&desc.shash, opad);
> 
> Basically it does not call final.
> Then call init again.
> 
> hw has certain limitation that it requires to process last block with 
> some bit set.
> WHen update is called there is no possibility to know that no more 
> update() will come.
> So possible last block is stored and then hashed out from the final.
> 
> I see that above code will not work with the driver.
> I wonder how intermediate export/import could be done with omap hw.
> 
> But if it's not possible, then why not to have hmac(sha1) as just sw.
> Anyway hmac should not process as huge amount of data as hash itself.
>
> What is your opinion/advice?

A sha1-only driver is not very useful since the biggest potential
user IPsec uses hmac(sha1).

Is the omap hw documentation available publicly?

Thanks,
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