Re: [Cryptography-dev] hash.SHA256 cpu expensive per byte versus byte-string?

2016-07-14 Thread lvh
Hi Frank, > On Jul 14, 2016, at 12:23 AM, Frank Siebenlist > wrote: > > Python's native hashing module (hashlib), shows similar results: > - about the same time when passed the 8MB blob in one go > (probably expected as both use openssl) > - substantial overhead when looping over small chunks (

Re: [Cryptography-dev] hash.SHA256 cpu expensive per byte versus byte-string?

2016-07-14 Thread Frank Siebenlist
> The perf by chunk is a consequence of how SHA256 works. I politely disagree... Having chunks smaller or larger than SHA256's 64 byte block size doesn't seem to affect the timing results in any noticeable way. If you do not fill-up SHA256's block-size buffer with update(), it simply returns, an

Re: [Cryptography-dev] hash.SHA256 cpu expensive per byte versus byte-string?

2016-07-14 Thread Donald Stufft
> On Jul 14, 2016, at 1:23 AM, Frank Siebenlist > wrote: > > Guess hashlib used some better optimization on the C-calls (?). > > This is my last update on this observation. > Conclusion is "so be it", and using bigger chunks for hashing gives > (much) better performance. I believe this is go