Get message digest generally by elixir-lang.

Crypto.ex

defmodule Crypto do
    def gethash(typ, s) do
        list_to_binary(Enum.map(bitstring_to_list(:crypto.hash(typ, s)), fn(x) -> integer_to_binary(x, 16) end))
    end
    def sha1(s), do:    gethash(:sha, s)    
    def md5(s), do:     gethash(:md5, s)
    def sha256(s), do:   gethash(:sha256, s)
    def sha512(s), do:   gethash(:sha512, s)
end