Novena Hash Contest Code
This is code I banged out in a day or two for the Novena laptop hash contest. The idea of the contest was to find hash collisions for an md5 hash, where at least N bits matched, with N potentially varying to adjust difficulty.
I started with a crappy basic method, then added some inline assembly using the POPCNT instruction to make it much faster, than progressed to using Hashcat and AWS GPU instances, and coordinated it all via RabbitMQ and AMQP. I could spin new instances in AWS and they'd auto-find the main server and start working on hashes.
Of course, I did this far too late in the contest and didn't get anywhere, and also realized that my approach was shitty and needed much refineement. But I did find some hashes!
Ah well, it was fun!!
Interesting Bits
Since it's a pile of hack, I figured I should point out interesting bits.
The code for the quick 128-bit math using POPCNT is handy if you do such things, and there is a rapid-ish generator of valid UTF8 characters in there. Mostly valid as far as I can tell. May not be every code point out there, but it was sufficient for the contest. It's pretty brute-force, if I recall.