KVL-Are Logical IDs necessary to Rx DES-OFB?

[billlayton]

We have been reading about loading encryption keys into the Motorola KVL.

The manual says each key must be associated with a single Logical ID.

Does the Logical ID apply to transmit only on Astro trunked systems?

In other words, would any Logical ID work for receive as long as the encryption key was correct (on an Astro trunked system)?

tKS,
Bill

[tvsjr]

No. The encrypted data stream contains the LID in an unencrypted format. If the radio has no key loaded with a matching LID, you get no audio. If it has a key with a matching LID, the radio will decode the audio - if the key is wrong, you get garbage... if the key is right, you get audio.

In short, yes, the LID matters.

[MattSR]

Terry is right - when a subscriber radio receives an encrypted transmission, it looks for a key with a matching LID and AlgoID. If it doesn't find something that matches those two fields, the radio stays muted.