In the hit US TV series The Wire police are initially baffled when the criminal suspects they are investigating begin to communicate through photographic messages of clock faces.
After several seasons of plots driven by the legalities and logistics of setting up telephone intercepts on suspected drug dealers, the police can’t keep up when overheard conversations are replaced by an inscrutable form of pictorial code.
The Wire cops eventually break the clock-face code but they’d have a great deal more difficulty in 2018 if they were chasing criminals using WhatsApp, Wicker, iMessage or other encrypted communications.
End-to-end encryption is a code so strong that only the communicating users can read the messages.
https://www.theguardian.com/technology/2018/dec/08/australias-war-on-encryption-the-sweeping-new-powers-rushed-into-law