Interesting article:
https://www.vice.com/en/article/4a3n3j/backdoor-in-police-radios-tetra-burst
"A group of cybersecurity researchers has uncovered what they believe is an intentional backdoor in encrypted radios used by police, military, and critical infrastructure entities around the world. The backdoor may have existed for decades, potentially exposing a wealth of sensitive information transmitted across them, according to the researchers."
Secure is never totally secure, right?