Clearly what has happened to CZ is not a vulnerability in Signal, he has probably had his phone hacked and had access to his data or there is a mole.

However, it is important to understand the flaws in Signal that can lead to targeting:

- Centralized servers

- Metadata collection

- Not anonymous, requires a phone number.

Simplex solves all these problems:

- Decentralized and you can set up your own receiving server or as many as you want for each contact.

- No user IDs, a new identity is generated for each contact or group, which makes metadata collection complicated.

- It is anonymous.