Automated Symbolic Verification of
Telegram’s MTProto 2.0
Within this model, we have provided a
fully automated proof of the soundness of MTProto 2.0’s protocols for first authentication,
normal chat, end-to-end encrypted chat, and re-keying mechanisms with respect to several
security properties, including authentication, integrity, confidentiality and perfect forward
secrecy. These properties are verified also in presence of malicious servers. Our formalization
covers also the behaviour of the users, when relevant; for instance, we have proved that if
the users do not check the fingerprints of their shared keys, a MITM attack is possible.
In the light of these results, we can affirm that MTProto 2.0 does not present any logical
flaw. Vulnerabilities can arise only from the cryptographic primitives, from implementation
flaws (e.g. insufficient checks), from side-channels exfiltration (such as timing or traffic
analysis), or from incorrect user behaviour.
https://arxiv.org/pdf/2012.03141v1.pdf
