On 10/03/2012 02:06 AM, David Miller wrote:
From: Jeff Garzik <jeff@xxxxxxxxxx>
Date: Wed, 3 Oct 2012 01:45:42 -0400
1) tcrypt setup blatantly wrong. What is the best setup here? Define a
separate entry for each digest length? Is there some special string
descriptor format that is desired, like "sha3-256" or "sha3(256)"?
Good question. The base name should probably be something without
dashes. Maybe "sha3_256", but yeah "sha3256" would look rediculous.
Well, the more basic question was... what to do when the digest length
is easily variable, vis a vis kernel hash APIs?
Keccak message digest size may fall anywhere within the range 8 bits -
1600 bits at runtime. You choose the digest size when you init the
context. In contrast, the kernel interface appears to require a
hardcoded size, chosen at driver compile time.
My patch picks sizes found in common use, consistent with existing
kernel practice. However, it is valid for another Keccak user to
produce a 1600 bit hash, or a 1592 bit hash, or a 1584 bit hash, etc., etc.
Maybe my patch is the best we can do in the current kernel, if dynamic
digest size is not currently possible. Register "sha3_224", "sha3_256",
... as you describe, and wait for actual users to appear with
unsupported digest sizes.
Jeff
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