More is Less: On the End-to-End Security of Group Chats in Signal, WhatsApp, and Threema

Rösler, Paul; Mainka, Christian; Schwenk, Jörg

doi:10.1109/eurosp.2018.00036

Cited by 78 publications

(42 citation statements)

References 16 publications

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“…We survey some of the most popular, giving asymptotic efficiencies for three main designs in Table 1 on the next page. In concurrent work, [44] examine the group messaging protocols used by WhatsApp, Signal and Threema, finding a number of vulnerabilities related to their group operations.…”

Section: Deployed Implementationsmentioning

confidence: 99%

On Ends-to-Ends Encryption

Cohn-Gordon

Cremers

Garratt

et al. 2018

Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security

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In the past few years secure messaging has become mainstream, with over a billion active users of end-to-end encryption protocols such as Signal. The Signal Protocol provides a strong property called post-compromise security to its users. However, it turns out that many of its implementations provide, without notification, a weaker property for group messaging: an adversary who compromises a single group member can read and inject messages indefinitely. We show for the first time that post-compromise security can be achieved in realistic, asynchronous group messaging systems. We present a design called Asynchronous Ratcheting Trees (ART), which uses tree-based Diffie-Hellman key exchange to allow a group of users to derive a shared symmetric key even if no two are ever online at the same time. ART scales to groups containing thousands of members, while still providing provable security guarantees. It has seen significant interest from industry, and forms the basis for two draft IETF RFCs and a chartered working group. Our results show that strong security guarantees for group messaging are practically achievable in a modern setting. CCS CONCEPTS • Security and privacy → Security protocols; Cryptography; Formal methods and theory of security; Formal security models; Mobile and wireless security;

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Section: Deployed Implementationsmentioning

confidence: 99%

On Ends-to-Ends Encryption

Cohn-Gordon

Cremers

Garratt

et al. 2018

Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security

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“…Existing secure group messaging protocols maintain the confidentiality and integrity properties in the presence of all types of adversary [4,15]. Closeness is sometimes weaker in existing protocols: for example, WhatsApp does not guarantee closeness in the presence of a malicious server [13]. However, group key agreement protocols that ensure closeness have been studied previously [7], so we do not consider this property further in this paper.…”

Section: Threat Model and Security Objectivesmentioning

confidence: 99%

“…(Sometimes transcript consistency is taken to mean that all group members must receive the same sequence of messages in the same order; for our purposes, it is su cient to require the weaker property that collaborators must receive the same set of messages, regardless of order.) Not all messaging protocols provide this property; for example, Signal does not ensure transcript consistency in the presence of a malicious user [13]. However, the property can be implemented as a separate layer on top of an existing messaging protocol.…”

Section: Convergence Of Shared Statementioning

confidence: 99%

From Secure Messaging to Secure Collaboration

Kleppmann

Kollmann

Vasile

et al. 2018

Security Protocols XXVI

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We examine the security of collaboration systems, where several users access and contribute to some shared resource, document, or database. To protect such systems against malicious servers, we can build upon existing secure messaging protocols that provide end-to-end security. However, if we want to ensure the consistency of the shared data in the presence of malicious users, we require features that are not available in existing messaging protocols. We investigate the protocol failures that may arise when a new collaborator is added to a group, and discuss approaches for enforcing the integrity of the shared data.

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“…Whatsapp uses Off the Record, Perfect Forward Secrecy and Double Ratchet Algorithm [8], [9] to secure all message communications on Whatsapp [10] and even databases that are used as data storage as well in passwords using unique keys and it will not same for every device that installed Whatsapp like smartphone android or apple smartphones, by using 3 algorithms for secure message it doesn't mean guarantee the message were safety and not known by others. Tools such as Analyzer for Whatsapp used to analyze words or phrases it take all the data messages that are in Whatsapp application and sent in the form of text to email and maybe there is a function in application to backup data server that developer used [11].…”

Section: Introductionmentioning

confidence: 99%

Insecure Whatsapp Chat History, Data Storage and Proposed Security

Siahaan¹,

Rahim²,

Aryza³

et al. 2018

Preprint

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Whatsapp is a social media application that is currently widely used from various circles due to ease of use and security is good enough, the security at the time of communicating at this time is very important as well with Whatsapp. Whatsapp from the network is very secure but on the local storage that contains the message was not safe enough because the message on local storage is not secured properly using a special algorithm even using the software Whatsapp Database Viewer whatsapp message can be known, to improve the security of messages on local storage whatsapp submitted security enhancements using the Modular Multiplication Block Cipher algorithm so that the message on whatsapp would be better in terms of security and not easy to read by unauthorized ones.

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More is Less: On the End-to-End Security of Group Chats in Signal, WhatsApp, and Threema

Cited by 78 publications

References 16 publications

On Ends-to-Ends Encryption

On Ends-to-Ends Encryption

From Secure Messaging to Secure Collaboration

Insecure Whatsapp Chat History, Data Storage and Proposed Security

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