Codec
A codec was a device or program that encoded or decoded a digital data stream.
In 2401, Doctor Beverly Crusher sent an encrypted distress call to Admiral Jean-Luc Picard's 2360s-era combadge. The distress call used an unusual codec which required a authorization code. When Picard realized that it was the Myriad codec, he supplied his authorization code and successfully opened Crusher's message. (PIC: "The Next Generation")