diff --git a/elixir/apps/domain/mix.exs b/elixir/apps/domain/mix.exs
index 688ad4948..33e9944ef 100644
--- a/elixir/apps/domain/mix.exs
+++ b/elixir/apps/domain/mix.exs
@@ -54,7 +54,7 @@ defmodule Domain.MixProject do
       # Auth-related deps
       {:plug_crypto, "~> 2.0"},
       {:openid_connect, github: "firezone/openid_connect", branch: "master"},
-      {:argon2_elixir, "~> 3.0"},
+      {:argon2_elixir, "~> 4.0"},
 
       # Erlang Clustering
       {:libcluster, "~> 3.3"},
diff --git a/elixir/mix.lock b/elixir/mix.lock
index 08c314953..42eafef87 100644
--- a/elixir/mix.lock
+++ b/elixir/mix.lock
@@ -1,6 +1,6 @@
 %{
   "acceptor_pool": {:hex, :acceptor_pool, "1.0.0", "43c20d2acae35f0c2bcd64f9d2bde267e459f0f3fd23dab26485bf518c281b21", [:rebar3], [], "hexpm", "0cbcd83fdc8b9ad2eee2067ef8b91a14858a5883cb7cd800e6fcd5803e158788"},
-  "argon2_elixir": {:hex, :argon2_elixir, "3.2.1", "f47740bf9f2a39ffef79ba48eb25dea2ee37bcc7eadf91d49615591d1a6fce1a", [:make, :mix], [{:comeonin, "~> 5.3", [hex: :comeonin, repo: "hexpm", optional: false]}, {:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "a813b78217394530b5fcf4c8070feee43df03ffef938d044019169c766315690"},
+  "argon2_elixir": {:hex, :argon2_elixir, "4.0.0", "7f6cd2e4a93a37f61d58a367d82f830ad9527082ff3c820b8197a8a736648941", [:make, :mix], [{:comeonin, "~> 5.3", [hex: :comeonin, repo: "hexpm", optional: false]}, {:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "f9da27cf060c9ea61b1bd47837a28d7e48a8f6fa13a745e252556c14f9132c7f"},
   "bunt": {:hex, :bunt, "0.2.1", "e2d4792f7bc0ced7583ab54922808919518d0e57ee162901a16a1b6664ef3b14", [:mix], [], "hexpm", "a330bfb4245239787b15005e66ae6845c9cd524a288f0d141c148b02603777a5"},
   "bureaucrat": {:hex, :bureaucrat, "0.2.9", "d98e4d2b9bdbf22e4a45c2113ce8b38b5b63278506c6ff918e3b943a4355d85b", [:mix], [{:inflex, ">= 1.10.0", [hex: :inflex, repo: "hexpm", optional: false]}, {:phoenix, ">= 1.2.0", [hex: :phoenix, repo: "hexpm", optional: true]}, {:plug, ">= 1.0.0", [hex: :plug, repo: "hexpm", optional: false]}, {:poison, "~> 1.5 or ~> 2.0 or ~> 3.0 or ~> 4.0", [hex: :poison, repo: "hexpm", optional: true]}], "hexpm", "111c8dd84382a62e1026ae011d592ceee918553e5203fe8448d9ba6ccbdfff7d"},
   "bypass": {:hex, :bypass, "2.1.0", "909782781bf8e20ee86a9cabde36b259d44af8b9f38756173e8f5e2e1fabb9b1", [:mix], [{:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: false]}, {:ranch, "~> 1.3", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "d9b5df8fa5b7a6efa08384e9bbecfe4ce61c77d28a4282f79e02f1ef78d96b80"},