This project and election demo using Homomorphic Encryption was created as part of the course "Advanced Security" given at the University of Geneva with the general goal being the demonstration of an election process with accurate results while working in the encrypted world, a personal choice of mine inspired by the 1988 PhD Thesis of J. C. Benaloh on the same topic.
The full documentation explaining the theoretical concepts behind it, motivation, implementation, and performance, can be found here.
As Python was my language of choice used to create this demo, a highly effective and optimized library known as Pyfhel was used. It essentially stands as a Python API for the other well-known C++ HE library developed by Microsoft, SEAL, given that the vote count is based on its implementation of the additive Paillier Scheme or RSA's multiplicative property.
Two important parameters called the plaintext modulus p, and the polynomial coefficient modulus m must be set on the HE_context.py file. These are two key parameters since they affect the whole behaviour of ciphertexts during encryption/decryption and addition for the election result.
m is a power of 2 (starting from 1024) and its increase directly increases ciphertext sizes too, allowing more encrypted operations and security however resulting in a hefty performance increase aswell.
During the election simulation on the command line, the user is asked to type the password given by the election authorities. This was added as a simple method to demonstrate an exchange of passwords from the election authorities to administrators on a local level and can be found and customized in the adminpass.txt file.
The default password is: bern
The simulation of an election using Partially Homomorphic Encryption can be started by simply running the main.py file which will start a custom election defined by the user on the command line.
In addition to that, this demo can be tested for perfomance, results, and decryption failures by running the simulate_election.py file with custom run parameters defined by the variables on the same file.