Kairos is a Peer-2-Peer capable framework for end-to-end verifiable voting systems, started as a fork of Helios by Ben Adida (https://github.com/benadida/helios-server) and eventually re-designed from scratch.

Github repo: https://github.com/biscofil/kairos_php

Thesis in PDF: http://hdl.handle.net/10579/19696

Kairos implements a modular structure which allows to handle multiple question types, cryptosystems and anonymization methods.

Supported anonymization methods	MixNets, Homomorphic encryption.
Supported question types	STV, Multiple choice and every question whose response can be encoded as a JSON dict
Supported Cryptosystems	ElGamal, RSA, Exp ElGamal
Supported Ballot encodings	JSON, small JSON