To ensure that the forward secrecy in long living chat session sessions, ''(n+1)sec'', provide provides a session key update through throughout the session. Each message sent to the session by each participant contains meta data described in [[#VIII.5.1 (n+1)sec Message Structure]]. Prior to sending any message, ''(n+1)sec'' instance, determines the content of meta data, and piggy back backs to that to the message according to the following algorithm:

We are using AES-256 in Galois/Counter Mode (GCM) with a shared group key for message encryption, we are following the suggestion by the original OTR protocol of using counter mode. However, unlike OTR, <math>(n+1)sec</math> does not support per message forgibility forgeability (although the whole transcript is forgibleforgeable), it is not prohibitive to use the same key for encryption and authentication.

The added authentication, spares p2p P@P send and receive routines from using digital signature.

The eQualit.ie team would like to give special thanks and note to the effort and dedication offered by Trevor Perrin and Ximin Luo to this project. They have been actively involved throughout the year and the result would not have been the same without their contribution. The team would also like to express thanks to Joseph Bonneau for his constructive comment and critisim to improve the protocol and its presentation. George Kadianakis for helping with the security proof and pointing out flaws and attack; Arlo Breault for his work on implementation of the protocol in the [https://github.com/equalitie/np1sec np1sec] software library; David Goulet for valuable advice as well as continued assistance and support offered to the project; Prof. Payman Mohassel for his help and advice on the security model and the proof; Prof. Jermey Clark, Prof. Matthew Green and Frederic Jacobs for their constructive participation in the design debates; Prof. Mark Manulis for suggesting the GKA. eQualit.ie expresses gratitude to Nadim Kobeissi, Cryptocat founder and developer who initiated the project and for sharing his experience and advices giving advice on the secure browser based chat. Last but not least we would like to thank the Open Technology Fund for supporting the project.