Authors: Eadan Plotnizky, Naama Scandarion

Programming Language: C++

This program lets a user choose if he wants to encrypt or decrypt a message using ElGamal cryptosystem, or the user can exit the program.

The testing of the random number to verify its primality is done using the Miller-Rabin primality test.

Encryption: The user will input a secret message to be encrypted and the bitsize to generate a random prime.

The output will show the prime number, private key, and cyphertext (gamma and delta).

Decryption: The user will input the prime number, private key, gamma and delta in order to decrypt the message. The output will be the message in decimal and text format

To run the program through VSCode make sure you have a G++ compiler.

InfInt.h by sercantutar - https://github.com/sercantutar/infint This program uses the InfInt library for simple lightweight large integer opereration and storage.

1. open Terminal
2. make sure you are in the right directory

3. type g++ .\ElGamal.cpp .\main.cpp -o .\main.exe -w to compile the program and to create an executable file.
4. type ./main.exe to run the executable through the terminal.

3. type g++ .\ElGamal.cpp .\main.cpp -o .\main.out -w to compile the program and to create an executable file.
4. type ./main.out to run the executable through the terminal.