Show HN: Accelerating SHA256 by 100x in Golang on ARM

Post by y4m4b4 » Wed, Jul 27, 2016, 10:56 PM UTC

DanielDent wrote: post #34

Did you compare performance to SHA512? Despite being a theoretically more secure/"harder" algorithm, on 64 bit platforms it can sometimes be faster than SHA256. If you don't want to use 512 bits, using 256 bits of the output of SHA512 is standardized as SHA512/256 and is considered valid/secure. (I'm unclear if this performance oddity remains true with the crypto hardware extensions being used here.)

Post by cperciva » Wed, Jul 27, 2016, 11:14 PM UTC

niftich wrote: post #21

WhitneyLand wrote: post #18

Earlier quoted context omitted.

My understanding is that SHA2 is fine for password storage, given a prudent number of hashing rounds.

It's fine to use a SHA2 variant HMAC in PBKDF2 with an obscene, ever-increasing number of rounds, but the scrypt paper [1] provides a detailed justification why you may want to switch to a dedicated password hashing function regardless. To quote their website [2]: "We estimate that on [circa-2009] hardware, if 5 seconds are spent computing a derived key, the cost of a hardware brute-force attack against scrypt is rou…

Post by gnaritas » Wed, Jul 27, 2016, 11:22 PM UTC

astrodust wrote: post #13

gnaritas wrote: post #6

So with hardware sha256, can this mine bitcoin cheaper than an ASIC?

Does it do terahashes per second? If not, then no.

Post by DannyBee » Wed, Jul 27, 2016, 11:43 PM UTC

giovannibajo1 wrote: post #31

white-flame wrote: post #29

Earlier quoted context omitted.

From a bird's eye view, adjust the compiler until it outputs the assembly you would have written. Hopefully this is done in such a way that such adjustments can be cross-beneficial across platforms, and can be easily created.

That's wishful thinking. GCC isn't able to do that with C language, a 20 years old compiler with a 40 years language. How would a compiler know that you can use a SHA2 instruction? Yes, there are intrinsics but then what about specialized vectorized instructions which don't match any primitive types or operations in the language (like, you can't express "add with carry" in C or Go)? And how can you explain a compiler…

Post by rukittenme » Thu, Jul 28, 2016, 12:02 AM UTC

smegel wrote: post #44

> minio/sha256-simd. So rather than writing your own module and a blog post bragging about it, why not just send a pull request to Golang core? There are lots of assembly code in there already dealing with special instructions on different architectures, there is nothing special about this. Or is being a humble programmer the antithesis of startup culture?