CoCoA: Concurrent Continuous Group Key Agreement

Alwen, Joël; Auerbach, Benedikt; Noval, Miguel Cueto; Klein, Karen; Pascual-Perez, Guillermo; Pietrzak, Krzyzstof; Walter, Michael

doi:10.1007/978-3-031-07085-3_28

Cited by 13 publications

(3 citation statements)

References 18 publications

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“…The CoCoA protocol [3] proposed a different approach to handle concurrent operations. In order to optimize communication while reconciling concurrent updates, the protocol employs a central server to safely merge updates on the shared structure: the key tree, and crafts usertailored message to communicate only the relevant updated keys.…”

Section: Protocol Handling Concurrent Operationsmentioning

confidence: 99%

See 1 more Smart Citation

DiSCreet: Distributed Delivery Service with Context-Aware Cooperation

Paillat,

Ignat,

Frey

et al. 2024

Preprint

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End-to-end encrypted messaging applications such as Signal became widely popular thanks to their capability to ensure the confidentiality and integrity of online communication. While the highest security guarantees were long reserved to two-party communication, solutions for n-party communication remained either inefficient or less secure until the standardization of the MLS Protocol (Messaging Layer Security). This new protocol offers an efficient way to provide end-to-end secure communication with the same guarantees originally offered by the Signal Protocol for two-party communication. However, both solutions still rely on a centralized component for message delivery, called the Delivery Service in the MLS Protocol. The centralization of the Delivery Service makes it an ideal target for attackers and threatens the availability of any protocol relying on MLS. In order to overcome this issue, we propose DiSCreet (Distributed delIvery Service with Context-awaRE coopEraTion), a design that allows clients to exchange protocol messages efficiently and without any intermediary. It uses a Probabilistic Reliable-Broadcast mechanism to efficiently deliver messages and the Cascade Consensus Protocol to handle messages requiring an agreement. Our solution strengthens the availability of the MLS Protocol without compromising its security. We compare the theoretical performance of DiSCreet with another distributed solution, the DGKA protocol, and detail the implementation of our solution.

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Section: Protocol Handling Concurrent Operationsmentioning

confidence: 99%

“…The approach adopted by TreeKEM and other protocols it inspired (e.g. [20], [3]) is to rely on a central authority to implement the Delivery Service. In this case, the Delivery Service would be operated by a central server.…”

Section: Centralized Delivery Servicementioning

confidence: 99%

DiSCreet: Distributed Delivery Service with Context-Aware Cooperation

Paillat,

Ignat,

Frey

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…The approach adopted by TreeKEM and other protocols it inspired (e.g. [15], [2]) is to rely on a central authority to implement the Delivery Service. In this case, the Delivery Service would be operated by a central server.…”

Section: Centralized Delivery Servicementioning

confidence: 99%

Design of an Efficient Distributed Delivery Service for Group Key Agreement Protocols

Paillat,

Ignat,

Frey

et al. 2024

Lecture Notes in Computer Science

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End-to-end encrypted messaging applications such as Signal became widely popular thanks to their capability to ensure the confidentiality and integrity of online communication. While the highest security guarantees were long reserved to two-party communication, solutions for n-party communication remained either inefficient or less secure until the standardization of the MLS Protocol (Messaging Layer Security). This new protocol offers an efficient way to provide end-to-end secure communication with the same guarantees originally offered by the Signal Protocol for two-party communication. However, both solutions still rely on a centralized component for message delivery, called the Delivery Service in the MLS Protocol. The centralization of the Delivery Service makes it an ideal target for attackers and threatens the availability of any protocol relying on MLS. In order to overcome this issue, we propose the design of a fully distributed Delivery Service that allows clients to exchange protocol messages efficiently and without any intermediary. It uses a Probabilistic Reliable-Broadcast mechanism to efficiently deliver messages and the Cascade Consensus Protocol to handle messages requiring an agreement. Our solution strengthens the availability of the MLS Protocol without compromising its security.

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