python RSA

A quick python script to create RSA keys and encrypt/decrypt files

Table of contents

• General info
• Technologies
• Usage

General info

With this script, you can:

• Create RSA Keys of any strenght
• Encrypt/Decrypt Files

Technologies

Uses the Miller-Rabin primality test, written in python by Ayrx, to find big prime numbers (154 digits by default) and the Extended Euclidean Algorithm to compute them into RSA Keys.

Usage

with files

To create RSA Keys, run RSA.py as following:

$ python RSA.py --genkeys filename

It will create two files, filename-public.key and filename-private.key

You can set the strenght of your key as following:

$ python RSA.py --genkeys filename -s 15

The above command will specifically ask the program to find 15 digits long prime numbers (154 digits long by default)

You can also encrypt or decrypt files as following:

$ python RSA.py --encrypt file -k key-public.key
$ python RSA.py --decrypt file-encrypted -k key-private.key

the encryption of file.txt will result in the creation (or update) of file-encrypted.txt, and the decryption of a file-encrypted.txt will be written in file.txt (it will try to remove the -encrypted in the name, if it can't find it will overwrite the encrypted file)

inside a script

you can also use this script inside yours by calling the getKeys(strenght) function of utils.py. the strenght is an int, use 154 if you want a strong key

The getKeys() function returns two tuples as following:

>>> public_key, private_key = getKeys(154)

with public_key = ( module , encryption_exponent ) and private_key = ( module , decryption_exponent )

you can then use encryptChar() and decryptChar() as following:

>>> encrypted_a = encryptChar('a',public_key)
>>> decryptChar(encrypted_a,private_key)
'a'

where encrypted_a is a long int

To import the function, you can use the following method:

import sys,os
sys.path.append(os.path.dirname(os.path.abspath(__file__))+'/python-RSA')
from utils import getKeys,encryptChar,decryptChar