diff --git a/flake.lock b/flake.lock
index 32c4dd7..094a98d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -21,11 +21,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
         "type": "github"
       },
       "original": {
@@ -37,11 +37,11 @@
     "nix-node-package": {
       "flake": false,
       "locked": {
-        "lastModified": 1706303050,
-        "narHash": "sha256-LCELgjzunxEsZQNRYJmVJ6FRVVurEsffed9aB8kPheE=",
+        "lastModified": 1694372307,
+        "narHash": "sha256-18dhHWJfa0QB0fPsaYvRwGd86BVn6xMkN6mDmiDKack=",
         "owner": "mkg20001",
         "repo": "nix-node-package",
-        "rev": "90f6ad8de81e3b75c2b0e6e3f9711bb094a5072b",
+        "rev": "97ac59276f12f768062e4eb336fc77079d5fb6a0",
         "type": "github"
       },
       "original": {
@@ -52,16 +52,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1718835956,
-        "narHash": "sha256-wM9v2yIxClRYsGHut5vHICZTK7xdrUGfrLkXvSuv6s4=",
+        "lastModified": 1703200384,
+        "narHash": "sha256-q5j06XOsy0qHOarsYPfZYJPWbTbc8sryRxianlEPJN0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "dd457de7e08c6d06789b1f5b88fc9327f4d96309",
+        "rev": "0b3d618173114c64ab666f557504d6982665d328",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-24.05",
+        "ref": "nixos-23.11",
         "type": "indirect"
       }
     },
@@ -99,11 +99,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1716159373,
-        "narHash": "sha256-3bO2jIWypYPzA9ezst55QyzIVErNt3tB+asi1ZJedPw=",
+        "lastModified": 1702764954,
+        "narHash": "sha256-+1z/0NJ/8c0d6Um1y9wpVO8CPXHd9/psOJF9GqFS/38=",
         "ref": "refs/heads/master",
-        "rev": "93f8a1b6a48e2b8f1daf784f7499a4651cac778c",
-        "revCount": 23,
+        "rev": "dcea3067863899ee23950670e7fed2a4feccc20e",
+        "revCount": 13,
         "type": "git",
         "url": "ssh://git@git.o-g.at/nixpkg/tuxpkgs.git"
       },
diff --git a/flake.nix b/flake.nix
index 478e95b..f0e0199 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,7 +1,7 @@
 {
   description = "Lenticular cloud interface";
   inputs = {
-    nixpkgs.url = "nixpkgs/nixos-24.05";
+    nixpkgs.url = "nixpkgs/nixos-23.11";
     flake-utils.url = "github:numtide/flake-utils";
     flake-compat = { # for shell.nix
       url = "github:edolstra/flake-compat";
diff --git a/lenticular_cloud/views/auth.py b/lenticular_cloud/views/auth.py
index 2752d5b..160aadd 100644
--- a/lenticular_cloud/views/auth.py
+++ b/lenticular_cloud/views/auth.py
@@ -113,7 +113,7 @@ async def login() -> ResponseReturnValue:
     options = webauthn.generate_authentication_options(
         rp_id = public_url.hostname,
         user_verification = UserVerificationRequirement.REQUIRED,
-        challenge=webauthn.helpers.generate_challenge()
+        challenge=webauthn.helpers.generate_challenge(32)
     )
     token = jwt.encode({
             'challenge': b64encode(options.challenge).decode(),