diff --git a/pyproject.toml b/pyproject.toml
index 5eb6947e..4031d850 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@ dependencies = [
     "Pillow>=10.0",
     # Federation crypto (sealed_box_v1): X25519, Ed25519, HKDF, XChaCha20-Poly1305.
     "cryptography>=41.0",
-    "pynacl>=1.5",
+    "pynacl>=1.6.2",
 ]
 
 [project.optional-dependencies]