[Lowfer] GWEN decode?

[Facility 406]

In a recent conversion with a fellow, we got to wondering if anyone had 
ever decrypted GWEN transmissions, other than the intended users, either 
when it was running, or after the fact?

Some GWEN info here:

https://en.wikipedia.org/wiki/AN/URC-117_Ground_Wave_Emergency_Network

More here:

https://nap.nationalacademies.org/read/2046/chapter/4#16

And from the link above, some information of the data format:

"for the GWEN data rate of 1,200 bits/sec. The actual GWEN signal at the 
LF carrier frequency consists of intermittent transmissions of packets 
carrying 644 uncorrelated MSK bits."

Any possible decode info out there?

Thanks.

Kurt