I very much doubt that the CCP has a backdoor into Signal the app; but it is worth keeping in mind that if an actor can observe traffic, e.g. cellular traffic r

I very much doubt that the CCP has a backdoor into Signal the app; but it is worth keeping in mind that if an actor can observe traffic, e.g. cellular traffic records or network flow logs, they may be able to correlate senders and receivers through ordinary time-stamps. Person A sends 200 bytes at time T, Person B receives 200 bytes at time T + 300ms. It doesn't take much analysis to build up a picture of a weighted network of communicators. There are "Military Grade" message and voice encryption technologies that avoid these issues by always sending a fixed amount of traffic to all parties, but that tends to be impractical for mobile apps.