With end-to-end encryption, only the people involved in a conversation can read the messages or hear the calls exchanged between them. This includes both 1-on-1 and group chats.

Viber's security technology creates an environment where two devices communicate using a secret code instead of plain, understandable text. Only the device sending the message and the device receiving the message have the key to decipher the code. Not even Viber can read and understand this code, and anyone who tries to hack or spy on this communication will not be able to understand it.