If you just want a checksum, rather than a cryptographically secure hash, Julia 0.6 has a hardware-accelerated CRC-32c checksum function (https://github.com/JuliaLang/julia/pull/18297). Currently it is unexported/undocumented, but that will likely change in the future.
In the meantime, you can do:
to read in the whole file and compute the checksum. Alternatively, you can checksum it in chunks by something like:
function checksum(filename, blocksize=16384)
crc = zero(UInt32)
open(filename, "r") do f
crc = Base.crc32c(read(f, blocksize), crc)
(The answer is independent of