Articles about Telegram:
https://blog.susanka.eu/tag/telegram/
Shortend version of my master thesis on Telegram:
https://www.susanka.eu/files/telegram-article.pdf
And the full thing:
https://www.susanka.eu/files/master-thesis-final.pdf
Slides from DEF CON 25:
https://www.susanka.eu/files/telegram-defcon-slides.pdf
Slides from ROOTS 2017:
https://www.susanka.eu/files/telegram-roots-slides.pdf
Tools available on GitHub:
https://github.com/tsusanka/telegram-deobfuscator
https://github.com/tsusanka/telegram-extractor