So what's the overall hashrate with this approach?

I'll try to calculate it from the information given. 12 parallel instances at a clock speed of 62.5MHz, with 68 clock cycles per hash.

62.5MHz * 12 / 68 = ~11MH/s

That seems... slow? Did I do the math right? How big of an FPGA do you need before this would compete with a GPU, and how much would it cost?

For reference, an RTX 4090 can do 21975.5 MH/s according to hashcat benchmarks.

More posts like this please! How about a crypto accelerator on FPGA that's integrated with OpenSSL?

Great job!

For alternative design/writeup, check out http://nsa.unaligned.org

Now try a fully unrolled/pipelined design that emits one hash per clock cycle for actual parallelization.

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