M4A: Unprotected audio file
M4A is a file extension for an audio file encoded with advanced audio coding (AAC) which is a loss compression. M4A was generally intended as the successor to MP3, which had not been originally designed for audio only but was layer III in an MPEG 1 or 2 video files. M4A stands for MPEG 4 Audio. M4A is an unprotected audio file.
A MAC (Media Access Control) address is an ID code assigned to any device with built-in networking capability. A MAC address is twelve digits and is usually displayed as six pairs of characters (hexadecimal) separated by colons or dashes (example - 0A:1B:2C:3D:4E:5F). Most manufacturer's web sites (along with others) can help users find the MAC address of a device; sometimes it is printed on a sticker on the device or the box it came in or included in documentation. Most of the time there will be two different MAC addresses printed on a sticker. One is for the wired Ethernet card and the other is for the wireless Ethernet card.
Multifactor Authentication/MFA (2-Step)
Multifactor authentication (MFA) is a security system that requires more than one method of authentication from independent categories of credentials to verify the user's identity for a login or other transaction.