Introduction

Additive homomorphic encryption based on ElGamal Encryption.

Use well-studied Elliptic Curve Ed25519 (Ed25519 implementation borrowed from Openssl)
Support up to 40-bit messages
Use baby-step-giant-step to accelerate decryption

Test

Please change MSG_BITS and BABY_BITS in lhe25519.h to smaller numbers for a faster test. For example,

#define MSG_BITS 20 #define BABY_BITS 10

To run our code, please execute the following commands:

cd build

cmake ..

make

./lhe

NOTE: You need to first generate the lookup table for the above tests to run successfully. Please check test.cpp for details.

There is no guarantee that this code is bug-free or has production-level security. Use it at your own risk.

zhicong303 AT gmail.com