Encrypted chats are secured by end-to-end encryption and are the most secure way to chat online without fear of being wiretapped. However, security requires vigilance: you must always be sure to verify digital fingerprints of every device that is involved in message exchange: both yours and your chat partner's.
Here is what you need to know about encrypted chats:
- Communication between clients is protected by OMEMO (OMEMO Multi-End Message and Object Encryption) protocol;
- Additionally, communication between clients and servers is protected by TLS (Transport Layer Security) protocol;
- OMEMO offers future and forward secrecy and deniability with message synchronization and offline delivery;
- Messages in Message Archive are encrypted and can only be decrypted by devices that were trusted by the sending device;
- Message synchronization between devices is only possible with trusted devices;
- Attacker with access to the server that stores your chat history can not read your encrypted chats.
The most realistic way to breach end-to-end encryption is via a so-called man-in-the-middle (MITM) attack. This attack is usually performed by an entity that has access to messaging server and alters the communications between two parties who believe that they are directly communicating with each other. To prevent such attack one must always verify the fingerprints of his chat partners. This should be done in a secure way, preferably, in person.