[api] Update stste_ecc.h functions parametters description

Author: Grom-

api/stse_ecc.h

@@ -50,7 +50,11 @@
  * \param[in] 	message_length 			Message length
  * \param[in] 	eddsa_variant 			Flag indicating a pre-hashed EdDSA (1) message or a pure EdDSA (0) plaintext message. Used only in case of Edwards25519 public key
  * \param[out] 	pSignature_validity		Signature validity flag (1 = valid signature, invalid otherwise)
- * \return \ref STSE_OK on success ; \ref stse_ReturnCode_t error code otherwise
+ * \return     \ref STSE_OK on success ; \ref stse_ReturnCode_t error code otherwise
+ *
+ * \note The expected signature format is the concatenation of R and S values (R|S as defined in ASN.1 DER encoding).
+         The public key format must match the expected ECC representation (typically concatenation of X and Y coordinates for uncompressed, or X with a prefix for compressed)
+ *
  * \details 	\include{doc} stse_ecc_verify_signature.dox
  */
 stse_ReturnCode_t stse_ecc_verify_signature(
@@ -68,11 +72,14 @@ stse_ReturnCode_t stse_ecc_verify_signature(
  * \details 	This API use the STSE to sign a message using a key in the requested slot
  * \param[in] 	pSTSE 					Pointer to STSE Handler
  * \param[in] 	slot_number 			Signature key slot
- * \param[in] 	key_type 				Signature key type
- * \param[in] 	pMessage 				Message to sign
- * \param[in] 	message_length 			Message length
- * \param[out] 	pSignature 				Signature buffer
- * \return \ref STSE_OK on success ; \ref stse_ReturnCode_t error code otherwise
+ * \param[in]  key_type        Signature key type
+ * \param[in]  pMessage        Message to sign
+ * \param[in]  message_length  Message length
+ * \param[out] pSignature      Signature buffer (concatenation of R and S)
+ * \return     \ref STSE_OK on success ; \ref stse_ReturnCode_t error code otherwise
+ * 
+ * \note The signature output is the concatenation of R and S values (R|S as defined in ASN.1 DER encoding).
+ * 
  * \details 	\include{doc} stse_ecc_generate_signature.dox
  */
 stse_ReturnCode_t stse_ecc_generate_signature(
@@ -92,7 +99,10 @@ stse_ReturnCode_t stse_ecc_generate_signature(
  * \param[in] 	pPublic_key 				Remote public key
  * \param[out] 	pShared_secret				Shared secret returned by the STSE
  * \return \ref STSE_OK on success ; \ref stse_ReturnCode_t error code otherwise
+ * 
  * \details 	\include{doc} stse_ecc_establish_shared_secret.dox
+ * 
+ * \note The public key format must match the expected ECC representation (typically concatenation of X and Y coordinates for uncompressed, or X with a prefix for compressed).
  */
 stse_ReturnCode_t stse_ecc_establish_shared_secret(
     stse_Handler_t *pSTSE,