AES and DES (Digital Encryption Standard) allows you to communicate with other radios that have the specific key programmed. RELM’s AES/DES Encryption is NIST certified, validated FIPS 140-2 Type III encryption with a 256 key load. If you order this with the radio, it will be installed before shipment. If you have a unit that needs this added, you will have to ship us the radio, we will get it installed, and turn it around ASAP.