Communication protocols determine how network components interact with each other. Therefore, the ability to derive a specification of a protocol can be useful in various contexts, such as to support deeper black-box testing or effective defense mechanisms. Unfortunately, it is often hard to obtain the specification because systems implement closed (i.e., undocumented) protocols, or because a time consuming translation has to be performed, from the textual description of the protocol to a format readable by the tools.

To address these issues, I've developed ReverX, a Java application that generates automata for the language and protocol state machine from network traces. Since this solution only resorts to interaction samples of the protocol, it is well-suited to uncover the message formats and protocol states of closed protocols and also to automate most of the process of specifying open protocols. It supports text-based protocols (eg, FTP, POP, etc.) and it provides a limited support for binary-based protocols (eg, DNS). It does not support encrypted payloads.