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defmodule Shard.Identity do
use Agent
require Salty.Sign.Ed25519, as: Sign
require Logger
@identity_db [Application.get_env(:shard, :data_path), "identity_db"] |> Path.join |> String.to_atom
def start_link(_) do
Agent.start_link(__MODULE__, :init, [], name: __MODULE__)
end
def init() do
:dets.start
{:ok, @identity_db} = :dets.open_file @identity_db, type: :set
case :dets.match @identity_db, :"$1" do
[] ->
Logger.info "Generating keypair..."
{pk, sk} = gen_keypair(Application.get_env(:shard, :peer_id_suffix))
nick_suffix = pk
|> binary_part(0, 3)
|> Base.encode16
|> String.downcase
nick = "Anon" <> nick_suffix
:dets.insert @identity_db, {pk, sk, nick}
%{
keypair: {pk, sk},
nickname: nick
}
[[{pk, sk, nick}] | _] ->
%{
keypair: {pk, sk},
nickname: nick
}
end
end
defp gen_keypair(suffix, n \\ 0) do
{:ok, pk, sk} = Sign.keypair
if rem(n, 10000) == 0 do
Logger.info "#{n}... expected #{:math.pow(256, byte_size(suffix))}"
end
if :binary.longest_common_suffix([pk, suffix]) == byte_size(suffix) do
{pk, sk}
else
gen_keypair(suffix, n+1)
end
end
def get_keypair() do
Agent.get(__MODULE__, &(&1.keypair))
end
def get_nickname() do
Agent.get(__MODULE__, &(&1.nickname))
end
def set_nickname(newnick) do
Agent.update(__MODULE__, fn state ->
{pk, sk} = state.keypair
:dets.insert @identity_db, {pk, sk, newnick}
%{state | nickname: newnick}
end)
end
end
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