diff --git a/include/polarssl/ecp.h b/include/polarssl/ecp.h
index 373de8d..ec9067d 100644
--- a/include/polarssl/ecp.h
+++ b/include/polarssl/ecp.h
@@ -296,14 +296,14 @@
  * \brief           Set a group from a TLS ECParameters record
  *
  * \param grp       Destination group
- * \param buf       Start of input buffer
+ * \param buf       &(Start of input buffer)
  * \param len       Buffer length
  *
  * \return          O if successful,
  *                  POLARSSL_ERR_MPI_XXX if initialization failed
  *                  POLARSSL_ERR_ECP_BAD_INPUT_DATA if input is invalid
  */
-int ecp_tls_read_group( ecp_group *grp, const unsigned char *buf, size_t len );
+int ecp_tls_read_group( ecp_group *grp, const unsigned char **buf, size_t len );
 
 /**
  * \brief           Write the TLS ECParameters record for a group