A small modification to John Bethencourt's libpaillier by making the decryption function run in constant time and make data-independent memory accesses.
The original version of libpaillier is here: http://acsc.cs.utexas.edu/libpaillier/
The original readme by John Bethencourt is in the README file.
This repository is not subject to the U.S. Export Administration Regulation (EAR) because it is publicly available; notifications to U.S. Bureau of Industry and Security (BIS) and National Security Agency (NSA) have been sent. For more information about this regulatory issue, see this post by Electronic Frontier Foundation (EFF).