We study the use of symmetric cryptography in the MTProto 2.0 protocol, Telegram's equivalent of the TLS record protocol. We give positive and negative results. On the one hand, we formally and in detail model a slight variant of Telegram's ``record protocol'' and prove that it achieves security in a suitable bidirectional secure channel model, albeit under unstudied assumptions; this model itself advances the state-of-the-art for secure ...

Production enterprises increasingly revert to digitization and data to gain insights and transparency in manufacturing environments. With the growing adoption of the Industrie 4.0 paradigm, the digital transformation of factories is in full swing. IIoT platforms, production management and manufacturing execution systems are installed in more and more production plants, which requires costly acquisition and customization. A significant ...

We introduce LTrack, a new tracking attack on LTE that allows an attacker to stealthily extract user devices' locations and permanent identifiers (IMSI). To remain stealthy, the localization of devices in LTrack is fully passive, relying on our new uplink/downlink sniffer. Our sniffer records both the times of arrival of LTE messages and the contents of the Timing Advance Commands, based on which LTrack calculates locations. LTrack is the ...

We develop machinery to design efficiently computable and consistent estimators, achieving estimation error approaching zero as the number of observations grows, when facing an oblivious adversary that may corrupt responses in all but an α fraction of the samples. As concrete examples, we investigate two problems: sparse regression and principal component analysis (PCA). For sparse regression, we achieve consistency for optimal sample ...