Protecting Network Traffic of One Billion: Reverse-Engineering Chinese Cryptography

Friday, July 12, 2024: 4:00 pm (Marillac Auditorium): TLS is not as universal as we might think! To this day, extremely popular Chinese applications use home-rolled network cryptography. Mona, Jeff, and Zoë have been reverse-engineering various home-...

Friday, July 12, 2024: 4:00 pm (Marillac Auditorium): TLS is not as universal as we might think! To this day, extremely popular Chinese applications use home-rolled network cryptography. Mona, Jeff, and Zoë have been reverse-engineering various home-rolled cryptography that protects hundreds of millions of users' sensitive data. They'll present various case studies from the past several years, including but not limited to: MMTLS, the custom cryptographic protocol that governs all WeChat traffic; various network encryption schemes used by popular Chinese keyboard apps; and flawed cryptography found in popular Chinese browsers. Their research found that faulty cryptography in multiple browsers and keyboard apps - each with hundreds of millions of users - effectively exposed every site visited and every keystroke made to any network eavesdropper. After studying and reporting the (often severe) flaws in these schemes, the companies mostly switched to standard cryptography like TLS.

The presentation will end with a call to action for hackers to help study the network encryption ecosystem in China, which continues to be overlooked by the modern security community.

Mona Wang
Jeffrey Knockel
Zoë Reichert