Telegram is a cloud-based mobile and desktop messaging app with a focus on security and speed. It is like SMS and email combined - fast, versatile and powerful. It is cross-platform app available for Android, Linux, Windows, Mac, and Windows Phone. You can send messages, photos, videos and files of any type (doc, zip, mp3, etc) to people who are in your phone contacts and have Telegram. You can also create groups for up to 200 people. With Telegram you can do all of this on any number of your devices, both mobile and desktop.
For those interested in maximum privacy, It offers Secret Chats, featuring end-to-end encryption to ensure that a message can only be read by its intended recipient. When it comes to Secret Chats, nothing is logged on our servers and you can automatically program the messages to self-destruct from both devices so there is never any record of it.
Atareao dedicated a PPA to telegram desktop client.
>>>Available for Ubuntu 14.10 Utopic/14.04 Trusty/12.04 Precise/Linux Mint 17.1/17/13/and other Ubuntu derivatives
To install Telegram Desktop Client in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal: