ActiveSupport MessageEncryptor Elixir HMAC ExCrypto

encryptor.ex

defmodule ActiveSupportMessageEncryptor do
  def encrypt(map, key) do
    clear_text = Poison.encode!(map)
    {:ok, aes_256_key} = Base.decode64(key)
    {:ok, {iv, cipher_text}} = ExCrypto.encrypt(aes_256_key, clear_text)
    payload = [cipher_text, iv] |> Enum.map(fn x -> Base.encode64(x) end) |> Enum.join("--") |> Base.encode64()
    digest = :crypto.hmac(:sha, aes_256_key, payload) |> Base.encode16(case: :lower)
    [payload, digest] |> Enum.join("--")
  end
end