Hi, According to the documentation it should be possible to call pjmedia_transport_srtp_create() with the "opt" argument set to NULL, it should just use the default SRTP settings. However, this pointer is referenced anyway in the code at line 386 (of transport_srtp.c): srtp->peer_use = opt->use; This should probably directly reference the default "use" parameter if opt == NULL. Ruud Klaver AG Projects