A. CLASSIFICATION OF SUBJECT MATTER INV. H04L29/06 G06F3/048 ADD. According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) H04L G06F Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and  where practicable  search terms used) EPO-Internal   WPI Data Special categories of cited documents : "T" later document published after the international filing date or priority "A" document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand to be of particular relevance the principle or theory underlying the invention Έ " earlier application or patent but published on or after the international filing date "X" document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive "L" document which may throw doubts on priority claim(s) orwhich is step when the document is taken alone rnational search report xel INTERNATIONAL SEARCH REPORT PCT/US2020/024350 International application No Form PCT/ISA/210 (second sheet) (April 2005)