Document the peer_key format for psa_key_agreement
@@ -3241,7 +3241,11 @@ psa_status_t psa_key_derivation(psa_crypto_generator_t *generator,
* \c PSA_CRYPTO_GENERATOR_INIT or
* psa_crypto_generator_init().
* \param private_key Slot containing the private key to use.
- * \param[in] peer_key Public key of the peer.
+ * \param[in] peer_key Public key of the peer. It must be
+ * in the same format that psa_import_key()
+ * accepts. The standard formats for public
+ * keys are documented in the documentation
+ * of psa_export_public_key().
* \param peer_key_length Size of \p peer_key in bytes.
* \param alg The key agreement algorithm to compute
* (\c PSA_ALG_XXX value such that
