diff --git a/dap-sdk/core/src/dap_common.c b/dap-sdk/core/src/dap_common.c
index 0a7aa08e40deba922de8896e0a0a13b1f330d6a5..d36d88e4575a670ce1774896f706fbe4436932a1 100755
--- a/dap-sdk/core/src/dap_common.c
+++ b/dap-sdk/core/src/dap_common.c
@@ -190,7 +190,7 @@ const char * dap_get_appname()
 }
 
 /**
- * @brief dap_set_appname
+ * @brief dap_set_appname set application name in global s_appname variable
  * @param a_appname
  * @return
  */
@@ -222,6 +222,16 @@ void dap_set_log_tag_width(size_t a_width) {
  * @param[in] a_log_file
  * @return
  */
+
+/**
+ * @brief dap_common_init call this function before using dap sdk modules
+ * 
+ * @param a_console_title set console title. Can be result of dap_get_appname()
+ * @param a_log_file_path path to log file. Saved in s_log_file_path variable
+ * @param a_log_dirpath path to log directory. Saved in s_log_dir_path variable
+ * @return int (0 if succcess, -1 if error)
+ */
+
 int dap_common_init( const char *a_console_title, const char *a_log_file_path, const char *a_log_dirpath) {
 
     // init randomer
diff --git a/dap-sdk/core/src/dap_file_utils.c b/dap-sdk/core/src/dap_file_utils.c
index 5844fcf3d712beaa08b1c617d4c8da43dfdebce3..30b3f7dc98effc0e4a69c5e6a0de728dcf81386f 100755
--- a/dap-sdk/core/src/dap_file_utils.c
+++ b/dap-sdk/core/src/dap_file_utils.c
@@ -114,12 +114,14 @@ bool dap_dir_test(const char * a_dir_path)
     return false;
 }
 
+
 /**
- * Create a new directory with intermediate sub-directories
- *
- * @dir_path new directory pathname
- * @return 0, if the directory was created or already exist, else -1
+ * @brief dap_mkdir_with_parents Create a new directory with intermediate sub-directories
+ * 
+ * @param a_dir_path new directory pathname
+ * @return int 0, if the directory was created or already exist, else -1
  */
+
 int dap_mkdir_with_parents(const char *a_dir_path)
 {
     // validation of a pointer
diff --git a/dap-sdk/core/src/dap_strfuncs.c b/dap-sdk/core/src/dap_strfuncs.c
index 118c040d0c300e38f7914faf20ca40bd923d5f15..f8944b88b34ef8fb956dfcb35036a7c188b07211 100755
--- a/dap-sdk/core/src/dap_strfuncs.c
+++ b/dap-sdk/core/src/dap_strfuncs.c
@@ -185,6 +185,14 @@ char *dap_itoa128(char *a_str, int128_t a_value, int a_base)
  *
  * Returns: length of the string
  */
+
+/**
+ * @brief dap_strlen get length of the string
+ * 
+ * @param a_str pointer to string
+ * @return size_t 
+ */
+
 size_t dap_strlen(const char *a_str)
 {
     size_t l_length = 0;
@@ -196,12 +204,13 @@ size_t dap_strlen(const char *a_str)
 }
 
 /**
- * dap_strcmp:
- * @a_str1: (nullable): the string
- * @a_str2: (nullable): the string
- *
- * Compare a_str1 and a_str2
+ * @brief dap_strcmp a_str1 and a_str2
+ * 
+ * @param a_str1 (nullable): the string
+ * @param a_str2 (nullable): the string
+ * @return int 
  */
+
 int dap_strcmp(const char *a_str1, const char *a_str2)
 {
     if(a_str1 && a_str2) {
@@ -211,12 +220,14 @@ int dap_strcmp(const char *a_str1, const char *a_str2)
 }
 
 /**
- * dap_strcmp:
- * @a_str1: (nullable): the string
- * @a_str2: (nullable): the string
- *
- * Compare a_n characters of a_str1 and a_str2
+ * @brief dap_strcmp
+ * 
+ * @param a_str1  (nullable): the string
+ * @param a_str2  (nullable): the string
+ * @param a_n Compare a_n characters of a_str1 and a_str2
+ * @return int 
  */
+
 int dap_strncmp(const char *a_str1, const char *a_str2, size_t a_n)
 {
     if(a_str1 && a_str2) {
@@ -225,16 +236,17 @@ int dap_strncmp(const char *a_str1, const char *a_str2, size_t a_n)
     return -1;
 }
 
+
 /**
- * dap_strdup:
- * @a_str: (nullable): the string to duplicate
- *
+ * @brief dap_strdup:
  * Duplicates a string. If @a_str is %NULL it returns %NULL.
  * The returned string should be freed
  * when no longer needed.
  *
- * Returns: a newly-allocated copy of @a_str
+ * @param a_str (nullable): the string to duplicate
+ * @return char* duplicated string
  */
+
 char* dap_strdup(const char *a_str)
 {
     char *l_new_str;
@@ -255,18 +267,21 @@ char* dap_strdup(const char *a_str)
 }
 
 /**
- * dap_strdup_vprintf:
- * @a_format: a standard printf() format string, but notice
- *     [string precision pitfalls][string-precision]
- * @a_args: the list of parameters to insert into the format string
- *
+ * @brief dap_strdup_vprintf
+ * 
  * Similar to the standard C vsprintf() function but safer, since it
  * calculates the maximum space required and allocates memory to hold
  * the result. The returned string should be freed with DAP_DELETE()
  * when no longer needed.
  *
  * Returns: a newly-allocated string holding the result
+ * 
+ * @param a_format  a standard printf() format string, but notice
+ *     [string precision pitfalls][string-precision]
+ * @param a_args the list of parameters to insert into the format string
+ * @return char* 
  */
+
 char* dap_strdup_vprintf(const char *a_format, va_list a_args)
 {
     char *l_string = NULL;
@@ -277,16 +292,18 @@ char* dap_strdup_vprintf(const char *a_format, va_list a_args)
 }
 
 /**
- * dap_strdup_printf:
- * @a_format: a standard printf() format string
- *
- * Similar to the standard C sprintf() function but safer, since it
+ * @brief dap_strdup_printf:
+ * 
+ *  * Similar to the standard C sprintf() function but safer, since it
  * calculates the maximum space required and allocates memory to hold
  * the result. The returned string should be freed with DAP_DELETE()
  * when no longer needed.
- *
- * Returns: a newly-allocated string holding the result
+ * 
+ * @param a_format a standard printf() format string
+ * @param ... 
+ * @return char* a newly-allocated string holding the result
  */
+
 char* dap_strdup_printf(const char *a_format, ...)
 {
     char *l_buffer;
@@ -630,6 +647,13 @@ char** dap_strsplit(const char *a_string, const char *a_delimiter, int a_max_tok
     return l_str_array;
 }
 
+/**
+ * @brief  dap_str_countv
+ * 
+ * @param a_str_array 
+ * @return size_t 
+ */
+
 size_t dap_str_countv(char **a_str_array)
 {
     size_t l_i = 0;
@@ -642,16 +666,19 @@ size_t dap_str_countv(char **a_str_array)
 }
 
 /**
- * dap_strdupv:
- * @a_str_array: (nullable): a %NULL-terminated array of strings
- *
+ * @brief  dap_strdupv:
+ * 
+ * @param a_str_array (nullable): a %NULL-terminated array of strings
  * Copies %NULL-terminated array of strings. The copy is a deep copy;
  * the new array should be freed by first freeing each string, then
  * the array itself. g_strfreev() does this for you. If called
  * on a %NULL value, g_strdupv() simply returns %NULL.
  *
  * Returns: (nullable): a new %NULL-terminated array of strings.
+ *
+ * @return char** 
  */
+
 char** dap_strdupv(const char **a_str_array)
 {
     if(a_str_array)
@@ -680,14 +707,16 @@ char** dap_strdupv(const char **a_str_array)
 }
 
 /**
- * dap_strfreev:
- * @a_str_array: (nullable): a %NULL-terminated array of strings to free
- *
+ * @brief dap_strfreev:
+ * 
  * Frees a %NULL-terminated array of strings, as well as each
  * string it contains.
  *
  * If @a_str_array is %NULL, this function simply returns.
+ *
+ * @param a_str_array (nullable): a %NULL-terminated array of strings to free
  */
+
 void dap_strfreev(char **a_str_array)
 {
     if(a_str_array)
@@ -701,9 +730,8 @@ void dap_strfreev(char **a_str_array)
 }
 
 /**
- * dap_strchug:
- * @a_string: a string to remove the leading whitespace from
- *
+ * @brief dap_strchug:
+ * 
  * Removes leading whitespace from a string, by moving the rest
  * of the characters forward.
  *
@@ -713,7 +741,11 @@ void dap_strfreev(char **a_str_array)
  *
  * The pointer to @a_string is returned to allow the nesting of functions.
  * Returns: @a_string
+ * 
+ * @param a_string a string to remove the leading whitespace from
+ * @return char* 
  */
+
 char* dap_strchug(char *a_string)
 {
     unsigned char *l_start;
@@ -760,15 +792,18 @@ char* dap_strchomp(char *a_string)
 }
 
 /**
- * dap_strup:
- * @a_str: a string
- * @a_len: length of @a_str in bytes, or -1 if @a_str is nul-terminated
- *
+ * @brief dap_strup
+ * 
  * Converts all lower case ASCII letters to upper case ASCII letters.
  *
  * Returns: a newly allocated string, with all the lower case
  *     characters in @a_str converted to upper case
+ * 
+ * @param a_str a string
+ * @param a_len  length of @a_str in bytes, or -1 if @a_str is nul-terminated
+ * @return char* 
  */
+
 char* dap_strup(const char *a_str, ssize_t a_len)
 {
     char *l_result, *l_s;
@@ -786,15 +821,17 @@ char* dap_strup(const char *a_str, ssize_t a_len)
 }
 
 /**
- * dap_strdown:
- * @a_str: a string
- * @a_len: length of @a_str in bytes, or -1 if @a_str is nul-terminated
- *
- * Converts all upper case ASCII letters to lower case ASCII letters.
+ * @brief  dap_strdown
+ *  Converts all upper case ASCII letters to lower case ASCII letters.
  *
  * Returns: a newly-allocated string, with all the upper case
  *     characters in @a_str converted to lower case
+ * 
+ * @param a_str a string
+ * @param a_len length of @a_str in bytes, or -1 if @a_str is nul-terminated
+ * @return char* 
  */
+
 char* dap_strdown(const char *a_str, ssize_t a_len)
 {
     char *l_result, *l_s;
@@ -811,10 +848,9 @@ char* dap_strdown(const char *a_str, ssize_t a_len)
     return l_result;
 }
 
+
 /**
- * dap_strreverse:
- * @a_string: the string to reverse
- *
+ * @brief dap_strreverse
  * Reverses all of the bytes in a string. For example,
  * `dap_strreverse("abcdef")` will result in "fedcba".
  *
@@ -822,7 +858,11 @@ char* dap_strdown(const char *a_str, ssize_t a_len)
  * containing multibyte characters.
  *
  * Returns: the same pointer passed in as @a_string
+ *
+ * @param a_string  the string to reverse
+ * @return char* 
  */
+
 char* dap_strreverse(char *a_string)
 {
     dap_return_val_if_fail(a_string != NULL, NULL);
@@ -857,6 +897,14 @@ char *strptime( char *buff, const char *fmt, struct tm *tm ) {
   return buff + len;
 }
 
+/**
+ * @brief _strndup
+ * 
+ * @param str 
+ * @param len 
+ * @return char* 
+ */
+
 char *_strndup(const char *str, unsigned long len) {
     char *buf = (char*)memchr(str, '\0', len);
     if (buf)
diff --git a/dap-sdk/crypto/src/dap_cert.c b/dap-sdk/crypto/src/dap_cert.c
index 920e16678ad35a37c074412ef3e620b6850ffceb..131b7415c5a152a088c75a78f4715d181bbb83d9 100755
--- a/dap-sdk/crypto/src/dap_cert.c
+++ b/dap-sdk/crypto/src/dap_cert.c
@@ -73,7 +73,7 @@ static dap_cert_item_t * s_certs = NULL;
 static dap_cert_folder_t * s_cert_folders = NULL;
 
 /**
- * @brief dap_cert_init
+ * @brief dap_cert_init empty stub for certificate init
  * @return
  */
 int dap_cert_init()
diff --git a/dap-sdk/crypto/src/dap_enc.c b/dap-sdk/crypto/src/dap_enc.c
index bb388202b73abac4f794c96408768490c7ad4102..507d62b52553d8e6e0eaab3ff8147b3bf351037d 100755
--- a/dap-sdk/crypto/src/dap_enc.c
+++ b/dap-sdk/crypto/src/dap_enc.c
@@ -35,9 +35,11 @@
 #define LOG_TAG "dap_enc"
 
 /**
- * @brief enc_init
- * @return
+ * @brief dap_enc_init if you want to use crypto functions from dap-sdk call that function
+ * 
+ * @return int 
  */
+
 int dap_enc_init()
 {
     srand(time(NULL));
diff --git a/dap-sdk/crypto/src/dap_enc_base58.c b/dap-sdk/crypto/src/dap_enc_base58.c
index 84282f26f97c1b9da2101a7b8274f93091f89f06..ad6c897a31beddb1ee04489d91bdbc19c10e389f 100755
--- a/dap-sdk/crypto/src/dap_enc_base58.c
+++ b/dap-sdk/crypto/src/dap_enc_base58.c
@@ -46,10 +46,10 @@ const int8_t c_b58digits_map[] = {
 };
 
 /**
- * @brief dap_enc_base58_decode
- * @param a_in
- * @param a_out
- * @return
+ * @brief dap_enc_base58_decode decode string using base58 alghoritm
+ * @param a_in - encoded string
+ * @param a_out - output buffer
+ * @return size_t output buffer size
  */
 size_t dap_enc_base58_decode(const char * a_in, void * a_out)
 {
@@ -152,8 +152,14 @@ size_t dap_enc_base58_decode(const char * a_in, void * a_out)
 }
 
 
-
-//bool b58enc(char *a_out, size_t *l_out_size, const void *a_in, size_t a_in_size)
+/**
+ * @brief dap_enc_base58_encode encode string in Base58 alghorithm
+ * 
+ * @param a_in - input buffer
+ * @param a_in_size - buffer size
+ * @param a_out - string with results
+ * @return size_t - returned string size (in bytes)
+ */
 size_t dap_enc_base58_encode(const void * a_in, size_t a_in_size, char * a_out)
 {
     const uint8_t *l_in_u8 = a_in;
diff --git a/dap-sdk/crypto/src/dap_enc_key.c b/dap-sdk/crypto/src/dap_enc_key.c
index 580127163d885d223b3d0857a501dde984c170f7..8d4c458ae07f8f42cae459bfb52610cc448de940 100755
--- a/dap-sdk/crypto/src/dap_enc_key.c
+++ b/dap-sdk/crypto/src/dap_enc_key.c
@@ -351,7 +351,7 @@ struct dap_enc_key_callbacks{
 
 const size_t c_callbacks_size = sizeof(s_callbacks) / sizeof(s_callbacks[0]);
 /**
- * @brief dap_enc_key_init
+ * @brief dap_enc_key_init empty stub
  * @return
  */
 int dap_enc_key_init()