diff --git a/lib/chronoscope/nts/key_establishment.ex b/lib/chronoscope/nts/key_establishment.ex
index 5e80e0e..677ba73 100644
--- a/lib/chronoscope/nts/key_establishment.ex
+++ b/lib/chronoscope/nts/key_establishment.ex
@@ -25,10 +25,7 @@ defmodule Chronoscope.NTS.KeyEstablishment do
   end
 
   def parse_response(response) do
-    response
-    |> do_parse_response(%{})
-    |> Map.update(:cookies, 0, &length/1)
-    |> then(&{:ok, &1})
+    {:ok, do_parse_response(response, %{})}
   end
 
   defp do_parse_response([], acc) do
diff --git a/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex b/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
index 80d6384..a593cae 100644
--- a/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
+++ b/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
@@ -13,16 +13,16 @@ defmodule ChronoscopeWeb.API.V1.NTS.KeyEstablishmentController do
 
     case NTS.key_establishment(host, port) do
       {:ok, configuration} ->
-        ok_response(conn, %{status: :ok, configuration: configuration})
+        json(conn, %{status: :ok, configuration: format_configuration(configuration)})
 
       {:error, error} ->
-        ok_response(conn, %{status: :error, reason: to_string(error)})
+        json(conn, %{status: :error, reason: to_string(error)})
     end
   end
 
-  defp ok_response(conn, body) do
-    conn
-    |> Plug.Conn.put_resp_content_type("application/json")
-    |> Plug.Conn.send_resp(:ok, Jason.encode!(body))
+  defp format_configuration(configuration) do
+    configuration
+    |> Map.take([:aead_algorithms, :cookie_length, :cookies, :next_protocols, :port, :server])
+    |> Map.update(:cookies, 0, &length/1)
   end
 end
diff --git a/test/chronoscope/nts/key_establishment_test.exs b/test/chronoscope/nts/key_establishment_test.exs
index 70f112a..c1e126a 100644
--- a/test/chronoscope/nts/key_establishment_test.exs
+++ b/test/chronoscope/nts/key_establishment_test.exs
@@ -9,96 +9,99 @@ defmodule Chronoscope.NTS.KeyEstablishmentTest do
   end
 
   test "handles empty response" do
-    assert KeyEstablishment.parse_response([]) == {:ok, %{cookies: 0}}
+    assert KeyEstablishment.parse_response([]) == {:ok, %{}}
+  end
+
+  test "ignores unkown record" do
+    assert KeyEstablishment.parse_response([0x80, 0x21, 0x00, 0x04, 0x00, 0x01, 0x02, 0x03]) == {:ok, %{}}
   end
 
   test "handles end of message record" do
-    assert KeyEstablishment.parse_response([0x80, 0x00, 0x00, 0x00]) == {:ok, %{cookies: 0}}
+    assert KeyEstablishment.parse_response([0x80, 0x00, 0x00, 0x00]) == {:ok, %{}}
   end
 
   test "handles next protocol negotiation record" do
-    assert KeyEstablishment.parse_response([0x80, 0x01, 0x00, 0x02, 0x00, 0x00]) ==
-             {:ok, %{cookies: 0, next_protocols: ["NTPv4"]}}
+    assert KeyEstablishment.parse_response([0x80, 0x01, 0x00, 0x02, 0x00, 0x00]) == {:ok, %{next_protocols: ["NTPv4"]}}
   end
 
   test "does not handle next protocol negotiation record without critical bit" do
-    assert KeyEstablishment.parse_response([0x00, 0x01, 0x00, 0x02, 0x00, 0x00]) == {:ok, %{cookies: 0}}
+    assert KeyEstablishment.parse_response([0x00, 0x01, 0x00, 0x02, 0x00, 0x00]) == {:ok, %{}}
   end
 
   test "handles empty next protocols" do
-    assert KeyEstablishment.parse_response([0x80, 0x01, 0x00, 0x00]) == {:ok, %{cookies: 0, next_protocols: []}}
+    assert KeyEstablishment.parse_response([0x80, 0x01, 0x00, 0x00]) == {:ok, %{next_protocols: []}}
   end
 
   test "handles multiple next protocols" do
     assert KeyEstablishment.parse_response([0x80, 0x01, 0x00, 0x06, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00]) ==
-             {:ok, %{cookies: 0, next_protocols: ["NTPv4", "UNASSIGNED", "NTPv4"]}}
+             {:ok, %{next_protocols: ["NTPv4", "UNASSIGNED", "NTPv4"]}}
   end
 
   test "handles aead algorithm negotiation record" do
     assert KeyEstablishment.parse_response([0x80, 0x04, 0x00, 0x02, 0x00, 0x0F]) ==
-             {:ok, %{cookies: 0, aead_algorithms: ["AEAD_AES_SIV_CMAC_256"]}}
+             {:ok, %{aead_algorithms: ["AEAD_AES_SIV_CMAC_256"]}}
   end
 
   test "handles aead algorithm negotiation record without critical bit" do
     assert KeyEstablishment.parse_response([0x00, 0x04, 0x00, 0x02, 0x00, 0x1E]) ==
-             {:ok, %{cookies: 0, aead_algorithms: ["AEAD_AES_128_GCM_SIV"]}}
+             {:ok, %{aead_algorithms: ["AEAD_AES_128_GCM_SIV"]}}
   end
 
   test "handles empty aead algorithms" do
-    assert KeyEstablishment.parse_response([0x80, 0x04, 0x00, 0x00]) == {:ok, %{cookies: 0, aead_algorithms: []}}
+    assert KeyEstablishment.parse_response([0x80, 0x04, 0x00, 0x00]) == {:ok, %{aead_algorithms: []}}
   end
 
   test "handles multiple aead algorithms" do
     assert KeyEstablishment.parse_response([0x80, 0x04, 0x00, 0x06, 0x00, 0x1E, 0x00, 0x01, 0x00, 0x0F]) ==
-             {:ok, %{cookies: 0, aead_algorithms: ["AEAD_AES_SIV_CMAC_256", "UNKNOWN", "AEAD_AES_128_GCM_SIV"]}}
+             {:ok, %{aead_algorithms: ["AEAD_AES_SIV_CMAC_256", "UNKNOWN", "AEAD_AES_128_GCM_SIV"]}}
   end
 
   test "handles error record" do
-    assert KeyEstablishment.parse_response([0x80, 0x02, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{cookies: 0, error: "Bad Request"}}
+    assert KeyEstablishment.parse_response([0x80, 0x02, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{error: "Bad Request"}}
   end
 
   test "handles unknown error record" do
-    assert KeyEstablishment.parse_response([0x80, 0x02, 0x00, 0x02, 0x00, 0x99]) == {:ok, %{cookies: 0, error: "153"}}
+    assert KeyEstablishment.parse_response([0x80, 0x02, 0x00, 0x02, 0x00, 0x99]) == {:ok, %{error: "153"}}
   end
 
   test "does not handle error record without critical bit" do
-    assert KeyEstablishment.parse_response([0x00, 0x02, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{cookies: 0}}
+    assert KeyEstablishment.parse_response([0x00, 0x02, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{}}
   end
 
   test "handles warning record" do
-    assert KeyEstablishment.parse_response([0x80, 0x03, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{cookies: 0, warning: "1"}}
+    assert KeyEstablishment.parse_response([0x80, 0x03, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{warning: "1"}}
   end
 
   test "does not handle warning record without critical bit" do
-    assert KeyEstablishment.parse_response([0x00, 0x03, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{cookies: 0}}
+    assert KeyEstablishment.parse_response([0x00, 0x03, 0x00, 0x02, 0x00, 0x01]) == {:ok, %{}}
   end
 
   test "handles server record" do
     assert KeyEstablishment.parse_response([0x80, 0x06, 0x00, 0x09, ?1, ?2, ?7, ?., ?0, ?., ?0, ?., ?1]) ==
-             {:ok, %{cookies: 0, server: "127.0.0.1"}}
+             {:ok, %{server: "127.0.0.1"}}
   end
 
   test "handles server record without critical bit" do
     assert KeyEstablishment.parse_response([0x00, 0x06, 0x00, 0x09, ?1, ?2, ?7, ?., ?0, ?., ?0, ?., ?1]) ==
-             {:ok, %{cookies: 0, server: "127.0.0.1"}}
+             {:ok, %{server: "127.0.0.1"}}
   end
 
   test "handles port record" do
-    assert KeyEstablishment.parse_response([0x80, 0x07, 0x00, 0x02, 0x04, 0xCE]) == {:ok, %{cookies: 0, port: 1230}}
+    assert KeyEstablishment.parse_response([0x80, 0x07, 0x00, 0x02, 0x04, 0xCE]) == {:ok, %{port: 1230}}
   end
 
   test "handles port record without critical bit" do
-    assert KeyEstablishment.parse_response([0x00, 0x07, 0x00, 0x02, 0x04, 0xCE]) == {:ok, %{cookies: 0, port: 1230}}
+    assert KeyEstablishment.parse_response([0x00, 0x07, 0x00, 0x02, 0x04, 0xCE]) == {:ok, %{port: 1230}}
   end
 
   test "handles cookie record" do
     assert KeyEstablishment.parse_response([0x80, 0x05, 0x00, 0x0E, ?c, ?h, ?o, ?c, ?o, ?l, ?a, ?t, ?e, ?_, ?c, ?h, ?i, ?p]) ==
-             {:ok, %{cookies: 1, cookie_length: 14}}
+             {:ok, %{cookies: ['chocolate_chip'], cookie_length: 14}}
   end
 
   test "handles cookie record without critical bit" do
     assert KeyEstablishment.parse_response([0x00, 0x05, 0x00, 0x0E, ?c, ?h, ?o, ?c, ?o, ?l, ?a, ?t, ?e, ?_, ?c, ?h, ?i, ?p]) ==
-             {:ok, %{cookies: 1, cookie_length: 14}}
+             {:ok, %{cookies: ['chocolate_chip'], cookie_length: 14}}
   end
 
   test "sets cookie length to longest cookie" do
@@ -107,7 +110,7 @@ defmodule Chronoscope.NTS.KeyEstablishmentTest do
                [0x80, 0x05, 0x00, 0x03, ?c, ?c, ?c] ++
                [0x80, 0x05, 0x00, 0x01, ?c]
            ) ==
-             {:ok, %{cookies: 3, cookie_length: 3}}
+             {:ok, %{cookies: ['c', 'ccc', 'c'], cookie_length: 3}}
   end
 
   test "handles full response" do
@@ -115,13 +118,14 @@ defmodule Chronoscope.NTS.KeyEstablishmentTest do
              [0x80, 0x01, 0x00, 0x02, 0x00, 0x00] ++
                [0x80, 0x04, 0x00, 0x06, 0x00, 0x1E, 0x00, 0x01, 0x00, 0x0F] ++
                [0x80, 0x05, 0x00, 0x01, ?c] ++
+               [0x00, 0x21, 0x00, 0x04, 0x00, 0x01, 0x02, 0x03] ++
                [0x80, 0x06, 0x00, 0x09, ?1, ?2, ?7, ?., ?0, ?., ?0, ?., ?1] ++
                [0x80, 0x07, 0x00, 0x02, 0x04, 0xCE] ++
                [0x80, 0x00, 0x00, 0x00]
            ) ==
              {:ok,
               %{
-                cookies: 1,
+                cookies: ['c'],
                 aead_algorithms: ["AEAD_AES_SIV_CMAC_256", "UNKNOWN", "AEAD_AES_128_GCM_SIV"],
                 cookie_length: 1,
                 next_protocols: ["NTPv4"],
@@ -133,6 +137,7 @@ defmodule Chronoscope.NTS.KeyEstablishmentTest do
   test "doesn't read past end of message record" do
     assert KeyEstablishment.parse_response(
              [0x80, 0x01, 0x00, 0x02, 0x00, 0x00] ++
+               [0x00, 0x21, 0x00, 0x04, 0x00, 0x01, 0x02, 0x03] ++
                [0x80, 0x04, 0x00, 0x02, 0x00, 0x1E] ++
                [0x80, 0x00, 0x00, 0x00] ++
                [0x80, 0x05, 0x00, 0x01, ?c] ++
@@ -141,7 +146,6 @@ defmodule Chronoscope.NTS.KeyEstablishmentTest do
            ) ==
              {:ok,
               %{
-                cookies: 0,
                 aead_algorithms: ["AEAD_AES_128_GCM_SIV"],
                 next_protocols: ["NTPv4"]
               }}