diff --git a/src/token/cose/crypto_impl/rustcrypto/encrypt/chacha_poly.rs b/src/token/cose/crypto_impl/rustcrypto/encrypt/chacha_poly.rs
index 57e13b9..9f2c5bd 100644
--- a/src/token/cose/crypto_impl/rustcrypto/encrypt/chacha_poly.rs
+++ b/src/token/cose/crypto_impl/rustcrypto/encrypt/chacha_poly.rs
@@ -7,6 +7,8 @@ use rand::CryptoRng;
 use rand::RngCore;
 
 impl<RNG: RngCore + CryptoRng> RustCryptoContext<RNG> {
+    /// Perform a ChaCha20/Poly1305 encryption operation on `plaintext` and the additional
+    /// authenticated data `aad` using the given `iv` and `key`.
     pub(super) fn encrypt_chacha20_poly1305(
         key: &CoseSymmetricKey<'_, <Self as CryptoBackend>::Error>,
         plaintext: &[u8],
@@ -16,6 +18,8 @@ impl<RNG: RngCore + CryptoRng> RustCryptoContext<RNG> {
         Self::encrypt_aead::<ChaCha20Poly1305>(key, plaintext, aad, iv)
     }
 
+    /// Perform a ChaCha20/Poly1305 decryption operation on `ciphertext_with_tag` and the additional
+    /// authenticated data `aad` using the given `iv` and `key`.
     pub(super) fn decrypt_chacha20_poly1305(
         key: &CoseSymmetricKey<'_, <Self as CryptoBackend>::Error>,
         ciphertext_with_tag: &[u8],