This thesis exposes a practical approach for the automatic reverse engineering of undocumented communication protocols. Current work in the field of automated protocol reverse engineering either infer incomplete protocol specifications or require too many stimulation of the targeted implementation with the risk of being defeated by counter-inference techniques. We propose to tackle these issues by leveraging the semantic of the protocol to improve the quality, the speed and the stealthiness of the inference process. This work covers the two main aspects of the protocol reverse engineering, the inference of its syntactical definition and of its grammatical definition. We propose an open-source tool, called Netzob, that implements our work to...