(n+1)sec is a secure group messaging protocol authored by eQualit.ie with support from the Open Technology Fund. It is also a free and open source software library. The main idea behind this project is to allow secure (sec) instantaneous communications between any number (n) of people. The protocol provides for end-to-end security of synchronous communications. It is efficient and builds on recent advancements in cryptographic research. Security properties of (n+1)sec include:
- Confidentiality: the conversation is not readable to an outsider
- Forward secrecy: conversation history remains unreadable to an outsider even if participants’ encryption keys are compromised
- Deniable authentication: Nobody can prove your participation in a chat
- Authorship: A message recipient can be assured of the sender’s authenticity even if other participants in the room try to impersonate the sender
- Room consistency: Group chat participants are confident that they are in the same room
- Transcript consistency: Group chat participants are confident that they are seeing the same sequence of messages
The protocol is being implemented as a FLOSS library in C++ and you can find it on our Github page.