A typical system for enabling multiple entities to exchanging data or communicate with one another may include a form of a distributed communication system, in which multiple parties to a communication are connected to each other through a network and a central hub or switch. In many circumstances, where that data being exchanged includes sensitive information, it is important to maintain privacy from external security threats. Additionally, in some circumstances, the network itself may not be reliably secure or trustworthy. For example, various parties engaging in a voice over Internet protocol (VoIP) teleconference may be speaking about sensitive information from various trusted locations throughout the world, but the telecommunication system or the central data mixer used to transmit the voice data between the parties may not be secure or trustworthy.
There has been prior work on the mixing of encrypted data, however, none of those approaches are compatible with the homomorphic encryption scheme such that privacy-preserving mixing can be performed for VoIP.
Moreover, these prior approaches do not cover encrypted VoIP teleconferencing, where encryption keys do not need to be shared with a VoIP mixer, in a manner that scales linearly with the number of participants (clients). Many consumer VoIP solutions do not support encryption of the signaling path or the media. As a result, the lack of encryption is a relative easy to eavesdrop on VoIP calls when access to the data network is possible.