> Some are saying this is impossible, that near real time decryption of 256-bit encryption is not possible.

This is very possible -- provided the other side has the keys to decrypt.

Note that "decrypt" is different from "crack". All these radios would "decrypt" in real time (because the receiving radio has the decryption keys). Cracking (as in decrypting, when you do not yet have the key) should be impossible.

But perhaps there is some flaw in the implementation that allows for "decrypting" without needing the keys. Most encrypted systems fall not because the algorithm (the 256-bit part you talk about) itself is weak, but because some other aspect of the overall implementation has a flaw that allows one to obtain the "secrets" without attacking the encryption.

And... Keep in mind that this report, assuming it is credible, could be as simple as: "The other side has captured one of the radios and is using it to listen in on the comms".