Added Independent RSA Communication Algorithm (#199)

* Added an indepedent RSA library

Added an indepedent RSA library with no depedences (adapted to communication)

* Created README.md

Created README.md

* Update README.md

* Added project to README.md

Added project "Independent RSA Communication Algorithm" to README.md

Co-authored-by: Ayush Bhardwaj <classicayush@gmail.com>
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@ -167,8 +167,10 @@ So far, the following projects have been integrated to this repo:
|[2048](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/2048)|[Krunal](https://github.com/gitkp11) |[2048](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/2048)|[Krunal](https://github.com/gitkp11)
|[Spotify Downloader](spotify_downloader)|[Sagar Patel](https://github.com/sagar627)| |[Spotify Downloader](spotify_downloader)|[Sagar Patel](https://github.com/sagar627)|
|[Download Page as PDF](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/Download-page-as-pdf)|[Jeremias Gomes](https://github.com/j3r3mias) |[Download Page as PDF](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/Download-page-as-pdf)|[Jeremias Gomes](https://github.com/j3r3mias)
|[Independent RSA Communication Algorithm](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/RSA_Communication)|[Miguel Santos](https://github.com/wi6n3l)
|[GithubBot](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/GithubBot)|[Abhilasha](https://github.com/Abhilasha06)| |[GithubBot](https://github.com/hastagAB/Awesome-Python-Scripts/tree/master/GithubBot)|[Abhilasha](https://github.com/Abhilasha06)|
## How to use : ## How to use :
- Clone/Download the directory and navigate to each folder. Or... - Clone/Download the directory and navigate to each folder. Or...

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# RSA Communication Script
## How to use
To use this script you may first open the script :p
It will take some time, it will generate two BIG prime numbers, and that takes some time.
After it finnishes calculating your keypair, it will print it and ask you if you want to encrypt or decrypt a message.
---
If you want to encrypt, you write "e" and then press enter. The script will ask you for a key (keypair) to encrypt your message, and here you paste the keypair of your correspondant
(the string that shows up at his/her script start).
After you paste the keypair you will write your message, and when you press enter the encrypted message will be printed.
---
If you want to decrypt a message, you write "d" and the press enter. Then the script will ask you for the message to decrypt, wich you are going to paste and press enter.
After you press enter the decrypted message will be displayed :)

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RSA_Communication/RSA.py Normal file
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#Modulus (N) bit length, k.
#OUTPUT: An RSA key pair ((N,e),d) where N is the modulus, the product of two primes (N=pq) not exceeding k bits in length;
# e is the public exponent, a number less than and coprime to (p1)(q1);
# and d is the private exponent such that e*d ≡ 1 mod (p1)*(q1).
##############################################################
#Select a value of e from 3,5,17,257,65537 (easy operations)
# while p mod e = 1
# p = genprime(k/2)
#
# while q mode e = 1:
# q = genprime(k - k/2)
#
#N = p*q
#L = (p-1)(q-1)
#d = modinv(e, L)
#return (N,e,d)
from random import randrange, getrandbits
import base64
class rsa():
def __init__(self, e=4, k=5):
self.e = [3, 5, 17, 257, 65537][e]
self.k = [128, 256, 1024, 2048, 3072, 4096][k]
def is_prime(self, n, tests=128):
if n == 2 or n == 3:
return True
if n <= 1 or n % 2 == 0:
return False
s = 0
r = n - 1
while r & 1 == 0:
s += 1
r //= 2
for _ in range(tests):
a = randrange(2, n - 1)
x = pow(a, r, n)
if x != 1 and x != n - 1:
j = 1
while j < s and x != n - 1:
x = pow(x, 2, n)
if x == 1:
return False
j += 1
if x != n - 1:
return False
return True
def genprime(self, length=1024):
p = 1
while len(bin(p))-2 != length:
p = list(bin(getrandbits(length)))
p = int(''.join(p[0:2] + ['1', '1'] + p[4:]), 2)
p += 1 if p % 2 == 0 else 0
ip = self.is_prime(p)
while not ip:
p += 2
ip = self.is_prime(p)
return p
def egcd(self, a, b):
if a == 0:
return (b, 0, 1)
else:
g, y, x = self.egcd(b % a, a)
return (g, x - (b // a) * y, y)
def modinv(self, a, m):
g, x, y = self.egcd(a, m)
if g != 1:
raise Exception('modular inverse does not exist')
else:
return x % m
def get_creds(self, e, k):
N = 0
while len(bin(int(N)))-2 != k:
p = self.genprime(int(k/2))
while pow(p, 1, e) == 1:
p = self.genprime(int(k/2))
q = self.genprime(k - int(k/2))
while pow(q, 1, e) == 1 and q == p:
q = self.genprime(k - int(k/2))
N = p*q
L = (p-1)*(q-1)
d = self.modinv(e, L)
return p, q, (d, e, N)
def get_keys(self):
p, q, creds = self.get_creds(self.e, self.k)
return creds
def save_keys(self, filename="keys.k"):
keys = self.get_keys()
with open(filename, "w", encoding="utf-8") as file:
file.write(str(keys[0]) + "\n" + str(keys[1]) + "\n" + str(keys[2]))
def load_keys(self, filename="keys.k"):
with open(filename, "r", encoding="utf-8") as file:
f = file.read().split("\n")
d = int(f[0])
e = int(f[1])
n = int(f[2])
return (d, e, n)
def encrypt(self, ke, plaintext):
key, n = ke
b64_string = base64.b64encode(plaintext.encode("utf-8")).decode("utf-8")
ready_code = []
for char in list(b64_string):
ready_code.append('0' * (3 - len(str(ord(char)))) + str(ord(char)))
ready_code = int("1" + "".join(ready_code))
cipher = pow(ready_code, key, n)
return cipher
def decrypt(self, kd, ciphertext):
key, n = kd
plain_list = list(str(pow(ciphertext, key, n)))[1:]
plain = []
count = 1
temp = ""
for i in plain_list:
if count != 4:
temp += i
count += 1
else:
plain.append(temp)
temp = i
count = 2
plain.append(temp)
plain_list = plain
plain = base64.b64decode(''.join([chr(int(char)) for char in plain_list])).decode("utf-8")
return plain
encryption = rsa()
keys = encryption.get_keys()
d = keys[0]
e = keys[1]
n = keys[2]
print("key: \n" + str(e) + "/" + str(n))
while True:
choose = input("Encrypt (e)/ Decrypt (d) > ")
if choose == "e":
e, n = input("insert key > ").split("/")
to_encrypt = input("message to encrypt > ")
a = encryption.encrypt((int(e), int(n)), to_encrypt)
print(a)
elif choose == "d":
to_decrypt = input("message to decrypt > ")
a = encryption.decrypt((d, n), to_decrypt)
print(a)