## Python, , rsa_key_generator.py

``````import os
import random
import sys

from . import cryptomath_module as cryptoMath
from . import rabin_miller as rabinMiller

def main() -> None:
print("Making key files...")
makeKeyFiles("rsa", 1024)
print("Key files generation successful.")

def generateKey(keySize: int) -> tuple[tuple[int, int], tuple[int, int]]:
print("Generating prime p...")
p = rabinMiller.generateLargePrime(keySize)
print("Generating prime q...")
q = rabinMiller.generateLargePrime(keySize)
n = p * q

print("Generating e that is relatively prime to (p - 1) * (q - 1)...")
while True:
e = random.randrange(2 ** (keySize - 1), 2 ** (keySize))
if cryptoMath.gcd(e, (p - 1) * (q - 1)) == 1:
break

print("Calculating d that is mod inverse of e...")
d = cryptoMath.find_mod_inverse(e, (p - 1) * (q - 1))

publicKey = (n, e)
privateKey = (n, d)
return (publicKey, privateKey)

def makeKeyFiles(name: str, keySize: int) -> None:
if os.path.exists("%s_pubkey.txt" % (name)) or os.path.exists(
"%s_privkey.txt" % (name)
):
print("\nWARNING:")
print(
'"%s_pubkey.txt" or "%s_privkey.txt" already exists. \n'
"Use a different name or delete these files and re-run this program."
% (name, name)
)
sys.exit()

publicKey, privateKey = generateKey(keySize)
print("\nWriting public key to file %s_pubkey.txt..." % name)
with open("%s_pubkey.txt" % name, "w") as out_file:
out_file.write(f"{keySize},{publicKey[0]},{publicKey[1]}")

print("Writing private key to file %s_privkey.txt..." % name)
with open("%s_privkey.txt" % name, "w") as out_file:
out_file.write(f"{keySize},{privateKey[0]},{privateKey[1]}")

if __name__ == "__main__":
main()
``````