hesham-rsa/rsa.py

#!/usr/bin/python3

#program to generate rsa key pair using methods in EE-305
# Hesham Banafa 

import math
import os

def main():

    #Prime of size 32 bit random
    print(getPrime(32))

def getPrime(bits):
    while True:
        x = int.from_bytes(os.urandom(int(bits/8)),"little")
        if isPrime(x):
            return x


def isPrime(number):
    if number == 2:
        return True

    #if 2 devides number then num is not prime. pg.21
    if number % 2 == 0 or number == 1:
        return False

    #largest integer less than or equal square root of number (K)
    rootOfNum = math.sqrt(number)
    K = math.floor(rootOfNum)

    #Take odd D such that 1 < D <= K
    #If D devides number then number is not prime. otherwise prime.
    for D in range(2, K):
        if D % 2 == 0:
            pass
        else:
            if number % D == 0 or number % 5 == 0:
                return False
    return True


if __name__ == "__main__":
    main()