Abstract: A non-transitory computer-readable medium storing instructions which when executed by a computer of a first client device cause the computer to perform a method of communicating via a chat session is provided. The method includes receiving, a request from a first user to begin the chat session with a second user. When the requested chat session is designated as a secret chat, first user data encrypted using a first key for encrypting data to be decrypted by a second client device associated with the second user is transmitted to the second client device. When the requested chat session is not designated as the secret chat, the first user data encrypted using a second key for encrypting data to be decrypted by the server is transmitted to the server for forwarding to the second client device.