diff --git a/crates/ctap2-proto/Cargo.toml b/crates/ctap2-proto/Cargo.toml
index 5139203..64aa113 100644
--- a/crates/ctap2-proto/Cargo.toml
+++ b/crates/ctap2-proto/Cargo.toml
@@ -12,4 +12,4 @@ coset = "0.3.3"
 serde = { version = "1.0", features = ["derive"], optional = true }
 
 [features]
-serde = ["dep:serde", "fido-common/serde"]
+serde = ["dep:serde", "fido-common/serde", "bounded-integer/serde1"]
diff --git a/crates/ctap2-proto/src/authenticator/device.rs b/crates/ctap2-proto/src/authenticator/device.rs
index a861799..0fe6166 100644
--- a/crates/ctap2-proto/src/authenticator/device.rs
+++ b/crates/ctap2-proto/src/authenticator/device.rs
@@ -7,8 +7,12 @@ use std::collections::{BTreeMap, BTreeSet};
 use std::num::NonZeroUsize;
 use std::usize;
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 /// A usize with a minimum value of N
 #[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct UsizeN<const N: usize>(bounded_integer::BoundedUsize<N, { usize::MAX }>);
 
 /// > data type byte string and identifying the authenticator model, i.e.