Re: [PATCH v4] poly1305: generic C can be faster on chips with slow unaligned access

[Eric Biggers]

On Tue, Nov 08, 2016 at 08:52:39AM +0100, Martin Willi wrote:
> 
> 
> Not sure what the exact alignment rules for key/iv are, but maybe we
> want to replace the same function in chacha20_generic.c as well?
> 
> Martin

chacha20-generic provides a blkcipher API and sets an alignmask of sizeof(u32)
- 1.  This applies to the key buffer for ->setkey() and to the mapped addresses
for the input/output buffers and IV during the blkcipher walk.  So it does not
appear to have the problems that poly1305 has.  

I do however see one small problem which is that
'u8 stream[CHACHA20_BLOCK_SIZE];' is, strictly speaking, not guaranteed to be
aligned to u32.

Eric