Two years ago when researchers found and publicly exposed an intentional backdoor in a TETRA encryption algorithm used to secure radio communications for police/military/intel agencies around the world -- the algorithm involved a key advertised as one strength but secretly reduced to 32 bits -- the European organization that produced the algorithm told users that to secure their communications they could deploy an end-to-end encryption solution on top of the backdoor'd algorithm. Now the same researchers say they found a security problem with the end-to-end solution as well -- another reduced key. Here's my story for Wired:

https://www.wired.com/story/encryption-made-for-police-and-military-radios-may-be-easily-cracked-researchers-find/