Apparatus for receiving, recording, transmitting, reproducing, storing, encrypting, decrypting sound or images, namely, digital data sending and receiving apparatus, set-top boxes for receiving multimedia content; multimedia players; television sets; players and recorders of high-definition optical disks, digital optical disks and compact disks; MP3 and MP4 players; multimedia tablet computers, mobile telephones, digital multimedia servers; computer servers, computers; modems, telecommunicati...