Security analysis of passcode mechanisms in Telegram and Viber

In: Bulletin of the Military University of Technology, Band 67, Heft 4, S. 183-194

Abstract

Telegram and Viber are the most popular mobile messengers nowadays. Unlike other
products, such as WhatsApp or Facebook Messenger, these messengers allow their users to restrict
access to messages stored on the device − in Telegram it is access protection using a PIN code, in the
Viber there is hidden chat functionality, also protected with a PIN code. This article presents a practical
attack that allows to bypass the security functionalities implemented by the developers of both solutions.
The paper presents the methods to increase the security of the mentioned software in a way that it can
be implemented in the Android operating system.
Keywords: Telegram, Viber, cryptography, Android, instant messenger.