Thread (70 messages) flat view 70 messages, 11 authors, 2016-12-18

Re: [PATCH v3 1/3] siphash: add cryptographically secure hashtable function

From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: 2016-12-14 23:34:37
Also in: linux-crypto, lkml

Hey Linus,

On Thu, Dec 15, 2016 at 12:30 AM, Linus Torvalds
[off-list ref] wrote:
No. The bug is talking about "words" in the first place.

Depending on your background, a "word" can be generally be either 16
bits or 32 bits (or, in some cases, 18 bits).

In theory, a 64-bit entity can be a "word" too, but pretty much nobody
uses that. Even architectures that started out with a 64-bit register
size and never had any smaller historical baggage (eg alpha) tend to
call 32-bit entities "words".

So 16 bits can be a word, but some people/architectures will call it a
"half-word".

To make matters even more confusing, a "quadword" is generally always
64 bits, regardless of the size of "word".

So please try to avoid the use of "word" entirely. It's too ambiguous,
and it's not even helpful as a "size of the native register". It's
almost purely random.

For the kernel, we tend use

 - uX for types that have specific sizes (X being the number of bits)

 - "[unsigned] long" for native register size

But never "word".
The voice of reason. Have a desired name for this function family?

siphash_3u64s
siphash_3u64
siphash_three_u64
siphash_3sixityfourbitintegers

Or does your reasonable dislike of "word" still allow for the use of
dword and qword, so that the current function names of:

siphash_3qwords
siphash_6dwords

are okay?

Jason
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