SAMOA

Secure and Scalable Platform for Massive-scale Mobile Applications
Project #PTDC/CCI-INF/32662/2017, 2018-2021, FCT/MCTES

Mobile applications have become the platform of choice for deploying innovative services. The interaction among users plays a central role in many of these novel applications, including multi-user games, applications for enhancing user experience in large events and touristic activities, among others. Traditional cloud-based architectures, where all interactions are mediated by servers lead to scalability and reliability issues.

In this project we propose adopting a decentralized architecture where mobile devices communicate directly and rely on cloud and edge resources for providing efficient, highly available and reliable solutions. To make these solutions a reality, we are focusing on the following three main challenges:

• Efficient communication among clients: we are developing efficient and robust overlay algorithms to support the communications among the elements of the system. These algorithms are combining the use of peer-to-peer connections among mobile client for fast interaction and the use of connections with edge and cloud node for providing robustness and ease management.
• Algorithms for partially replicated data: as each user is only interested in a small fraction of the data maintained by the system, and that the data evolves over time, it is necessary to develop algorithm for partial and dynamic replication.
• Security mechanisms: we are focusing primarily on preventing unauthorized operations, while still allowing fast peer-to-peer interaction among mobile nodes. In this context, we are working not only on algorithms for providing security guarantees but also on programming abstractions for dealing with the problem.

As a predecessor of this project, and extended during this project, we have built Legion, a framework for extending web applications with peer-to-peer interactions. Legion relies on WebRTC, STUN and TURN to allow web clients to securely replicate data objects and synchronize peer-to-peer. Legion relies on cloud services for providing data durability - it provides an API compatible with Google Drive Realtime. This was a result of SyncFree project (2013-16, UE FP7) and LightKone project (2017-19, UE H2020, 732505).

Open Positions

The project is finished but we are still doing research in the same topics - if you are a prospective MSc or phD student interested in these topics, send me a message for knowing more information.

Software

• Legion (http://legion.di.fct.unl.pt) : Legion framework.
  

Members

Sérgio Duarte
Bernardo Ferreira
João Leitão (co-PI)
João Lourenço
Albert van der Linde
Nuno Preguiça (PI)

References

• Geo-located data for better dynamic replication.. [PDF]
  Luís Silva, Frederico Aleixo, Albert van der Linde, João Leitão, Nuno Preguiça: Workshop on Principles and Practice of Consistency for Distributed Data (PaPoC '22). 2022.
• ECROs: building global scale systems from sequential code. [DOI | PDF ]
  Kevin De Porre, Carla Ferreira, Nuno Preguiça, and Elisa Gonzalez Boix: Proc. ACM Program. Lang. 5, OOPSLA, Article 107 (October 2021).
• Practical Client-side Replication: Weak Consistency Semantics for Insecure Settings. [DOI | PDF | Bibtex]
  Albert van der Linde, João Leitã̃o, and Nuno Preguiç̧a: PVLDB, 13(11): 2590-2605, 2020.
• The intrinsic cost of causal consistency. [DOI | PDF | Bibtex]
  Albert van der Linde, Pedro Fouto, João Leitão, and Nuno Preguiça. In Proceedings of the 7th Workshop on Principles and Practice of Consistency for Distributed Data (PaPoC '20). Article 11, 1–5. 2020.
• On combining fault tolerance and partial replication with causal consistency. [DOI | PDF | Bibtex]
  Albert van der Linde, Diogo Serra, João Leitão, and Nuno Preguiça. In Proceedings of the 7th Workshop on Principles and Practice of Consistency for Distributed Data (PaPoC '20). Article 11, 1–5. 2020.
• Data Replication on the Cloud/Edge [DOI | PDF | Bibtex]
  D. Mealha, N. Preguiça, M. Cecília Gomes, and J. Leitão.: in Proc. PaPoC 2019, 2019.
  
• IPA: Invariant-Preserving Applications for Weakly Consistent Replicated Databases [DOI | PDF | Bibtex]
  Valter Balegas, Sérgio Duarte, Carla Ferreira, Rodrigo Rodrigues, Nuno Preguiça: PVLDB, 12(4): 404-418, 2018.
  
• Legion: Enriching Internet Services with Peer-to-Peer Interactions [DOI | PDF | Bibtex]
  Albert van der Linde, Pedro Fouto, João Leitão, Nuno Preguiça, Santiago Castiñeira, and Annette Bieniusa: Proc. WWW'2017, 2017.
  
• Conflict-free Replicated Data Types [PDF | Bibtex]
  Marc Shapiro, Nuno Preguiça, Carlos Baquero and Marek Zawirski. In Proceedings of the 13th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2011), October 2011.