diff --git a/dap-sdk/crypto/src/dap_cert_file.c b/dap-sdk/crypto/src/dap_cert_file.c
index f3ef309e656ec3deee43becd89cbec70b523cbd2..52b76b66c0057c7e2a2ba72a4417778bb391a2d4 100755
--- a/dap-sdk/crypto/src/dap_cert_file.c
+++ b/dap-sdk/crypto/src/dap_cert_file.c
@@ -39,8 +39,9 @@ static const char s_key_inheritor[] = "Inheritor";
  * @brief dap_cert_file_save
  * @param a_cert
  * @param a_cert_file_path
- * @return
+ * @return int
  */
+
 int dap_cert_file_save(dap_cert_t * a_cert, const char * a_cert_file_path)
 {
     char * l_file_dir = dap_path_get_dirname(a_cert_file_path);
@@ -72,6 +73,15 @@ int dap_cert_file_save(dap_cert_t * a_cert, const char * a_cert_file_path)
 }
 
 // balance the binary tree
+
+/**
+ * @brief s_balance_the_tree
+ * 
+ * @param a_reorder 
+ * @param a_left_idx 
+ * @param a_right_idx 
+ */
+
 void s_balance_the_tree(dap_cert_file_aux_t *a_reorder, size_t a_left_idx, size_t a_right_idx)
 {
     if (a_left_idx == a_right_idx) {
@@ -86,6 +96,14 @@ void s_balance_the_tree(dap_cert_file_aux_t *a_reorder, size_t a_left_idx, size_
     }
 }
 
+/**
+ * @brief dap_cert_deserialize_meta
+ * 
+ * @param a_cert 
+ * @param a_data 
+ * @param a_size 
+ */
+ 
 void dap_cert_deserialize_meta(dap_cert_t *a_cert, const uint8_t *a_data, size_t a_size)
 {
     dap_cert_metadata_t **l_meta_arr = NULL;
@@ -152,6 +170,14 @@ void dap_cert_deserialize_meta(dap_cert_t *a_cert, const uint8_t *a_data, size_t
     DAP_DELETE(l_meta_arr);
 }
 
+/**
+ * @brief dap_cert_serialize_meta
+ * 
+ * @param a_cert 
+ * @param a_buflen_out 
+ * @return uint8_t* 
+ */
+
 uint8_t *dap_cert_serialize_meta(dap_cert_t *a_cert, size_t *a_buflen_out)
 {
     if (!a_cert) {
@@ -218,11 +244,12 @@ uint8_t *dap_cert_serialize_meta(dap_cert_t *a_cert, size_t *a_buflen_out)
 }
 
 /**
- * @brief dap_cert_file_save_to_mem
+ * @brief dap_cert_mem_save
  * @param a_cert
  * @param a_cert_size_out
- * @return
+ * @return uint8_t*
  */
+
 uint8_t* dap_cert_mem_save(dap_cert_t * a_cert, uint32_t *a_cert_size_out)
 {
     dap_cert_file_hdr_t l_hdr={0};
@@ -306,8 +333,8 @@ lb_exit:
 
 /**
  * @brief dap_cert_file_load
- * @param a_cert_file_path
- * @return
+ * @param a_cert_file_path: path to certificate, for example "{PREFIX}/var/lib/ca/node-addr.dcert"
+ * @return dap_cert_t
  */
 
 dap_cert_t* dap_cert_file_load(const char * a_cert_file_path)
@@ -338,10 +365,12 @@ lb_exit:
 
 /**
  * @brief dap_cert_mem_load
- * @param a_data
- * @param a_data_size
- * @return
+ * 
+ * @param a_data - pointer to buffer with certificate, early loaded from filesystem
+ * @param a_data_size - size of certificate
+ * @return dap_cert_t* 
  */
+
 dap_cert_t* dap_cert_mem_load(const void * a_data, size_t a_data_size)
 {
     dap_cert_t * l_ret = NULL;