`sha256("abc")` should give: ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad but calculates wrong 2bb53935edbba17dc04a04854518754d8a66484491b585b0d0700cd2512f5420 instead. See also https://stackoverflow.com/questions/22880627/sha256-implementation-in-c It seems not to be an endianess issue. Any idea?