What is the theoretical minimum number of logical operations an ASIC needs to perform to compute double iterated SHA256, i.e., sha(sha(•))?

  • Is this the best way to phrase the question? It seems like you'd want to know 1) the number of gates required to implement it, and 2) how much it can be pipelined (probably quite a lot.)
    – Nick ODell
    Apr 19, 2015 at 8:33

1 Answer 1


SHA256D, which is what Bitcoin uses, is 128 rounds, comprising

768 additions,

640 ORs

896 XORs

And a bunch of bit shifts but bit shifts are free on an ASIC.



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