diff --git a/wrapper/rust/wolfssl-wolfcrypt/src/rsa_pkcs1v15.rs b/wrapper/rust/wolfssl-wolfcrypt/src/rsa_pkcs1v15.rs
index cd0079beda..40314f9548 100644
--- a/wrapper/rust/wolfssl-wolfcrypt/src/rsa_pkcs1v15.rs
+++ b/wrapper/rust/wolfssl-wolfcrypt/src/rsa_pkcs1v15.rs
@@ -196,6 +196,8 @@ impl<H: Hash, const N: usize> SignerMut<Signature<N>> for SigningKey<H, N> {
     }
 }
 
+/// Maximum number of bytes that the E exponent can use. An error is returned
+/// if longer exponent byte arrays are provided.
 const MAX_E_LEN: usize = 8;
 
 /// RSA PKCS#1 v1.5 verifying key.