Alice and Bob, who the FOCI are they?: Analysis of end-to-end encryption in the LINE messaging application


Antonio M. Espinoza, William J. Tolley, and Jedidiah R. Crandall, UNM; Masashi Crete-Nishihata and Andrew Hilts, Citizen Lab


End-to-end encryption (E2EE) is becoming a standard feature in many popular chat apps, but independent security assessments of these implementations are limited. In this paper we provide the first independent analysis of E2EE features in LINE, a messaging application popular in Asian markets, and identify a replay attack and an attack on a lack of forward secrecy. Based on our analysis and communications with LINE about the vulnerabilities we discuss challenges and new research directions to better bridge vendors, researchers, and end-users around security issues.

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@inproceedings {205922,
author = {Antonio M. Espinoza and William J. Tolley and Jedidiah R. Crandall and Masashi Crete-Nishihata and Andrew Hilts},
title = {Alice and Bob, who the {FOCI} are they?: Analysis of end-to-end encryption in the {LINE} messaging application},
booktitle = {7th USENIX Workshop on Free and Open Communications on the Internet (FOCI 17)},
year = {2017},
address = {Vancouver, BC},
url = {},
publisher = {USENIX Association},
month = aug