Security analysis of passcode mechanisms in Telegram and Viber

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.