diff --git a/src/ed25519.rs b/src/ed25519.rs
index acf5fd0..81e9c36 100644
--- a/src/ed25519.rs
+++ b/src/ed25519.rs
@@ -28,6 +28,7 @@ use curve25519_dalek::curve::ProjectivePoint;
 use curve25519_dalek::scalar::Scalar;
 use curve25519_dalek::subtle::arrays_equal_ct;
 
+/// The length of an ed25519 `Signature`, in bytes.
 pub const SIGNATURE_LENGTH: usize = 64;
 
 /// An ed25519 signature.
diff --git a/src/lib.rs b/src/lib.rs
index f2f6345..3744e91 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -63,6 +63,7 @@
 #![feature(rand)]
 #![allow(unused_features)]
 #![cfg_attr(feature = "bench", feature(test))]
+#![deny(missing_docs)] // refuse to compile if documentation is missing
 
 #[macro_use]
 extern crate arrayref;