Implementation and Evaluation of the BUBBLE-BLUE Multihop Private Bluetooth Protocol

Inria, the French national research institute for the digital sciences

Organisation/Company Inria, the French national research institute for the digital sciences Research Field Computer science Researcher Profile First Stage Researcher (R1) Application Deadline 12 Apr 2026 - 00:00 (UTC) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 38.5 Offer Starting Date 1 May 2026 Is the job funded through the EU Research Framework Programme? Not funded by a EU programme Reference Number Is the Job related to staff position within a Research Infrastructure? No

Offer Description

The TRiBE team at Inria Saclay is offering a 6-month Research and Development Engineer position to implement a private Bluetooth-based communication protocol called BUBBLE-BLUE . BUBBLE-BLUE (BB) is a multihop private communication approach that enables a small group of devices to exchange messages using Bluetooth only, without relying on cellular or Wi‑Fi infrastructure. The protocol combines end‑to‑end confidentiality within the group with controlled multihop dissemination based on Connected Dominating Set (CDS) mechanisms. In practice, since Bluetooth does not natively support broadcasting, message dissemination relies on sequences of unicast transmissions.

• Implement an operational prototype of the BUBBLE‑BLUE protocol stack on the target device, including Bluetooth transport integration and a minimal demonstrator application (e.g., secure group chat and optional geo‑sharing).
• Explore and assess the security layer assumptions and implementation choices (key distribution, replay resistance, revocation/repudiation handling, overhead, and performance impact).
• Evaluate the resulting system under realistic constraints (mobility/density/traffic) and produce a report on the reproducible experimental results.
• Study the BUBBLE‑BLUE preprint to derive an implementable protocol specification, including packet formats, timers, and state machines.
• Define the interfaces between the Bluetooth transport layer, the protocol core for control and forwarding, and the application layer.
• Establish a reproducible test methodology, along with a logging and telemetry strategy, for experimental evaluation.
• Implement the baseline security and packet‑processing functions on the target device, including per‑packet session keys, encrypted payloads, multi‑recipient key headers, sequence numbers, and replay protection.
• Implement the baseline forwarding plane using controlled flooding based on a Connected Dominating Set (CDS) based distributed approaches.
• Explore and compare alternative routing and forwarding strategies, such as frugal AI‑based approaches.
• Conduct security analysis, protocol hardening, and experimental validation by assessing threats.
• Background in computer networks / wireless systems.
• Programming skills suitable for the target device (e.g., C/C++, Python, or embedded Linux).
• Familiarity with Bluetooth APIs/constraints is a plus.
• Basic understanding of applied cryptography and secure software engineering practices. Ability to run experiments, analyze results, and write a clear technical report.

Languages FRENCH Level Basic

Languages ENGLISH Level Good

Additional Information

• Partial reimbursement of public transport costs
• Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
• Possibility of teleworking (after 6 months of employment) and flexible organization of working hours
• Professional equipment available (videoconferencing, loan of computer equipment, etc.)
• Social, cultural and sports events and activities
• Access to vocational training
• Social security coverage

Regarding professional experience

Selection process

To apply, please provide :

• CV
• Letter(s) of recommendation, where applicable