Encryption-Methods

---

El-gamal

The files included in this project are:
elgamal_keygen.py
elgamal_encryption.py
elgamal_decryption.py
plain_text_el_gamal.txt
ciphertext_elgamal.txt
decipher_elgamal.txt
elgamal_runtime.txt
private_key_el_gamal.txt
public_key_el_gamal.txt

File usage:

elgamal_keygen.py is used to generate the public and private keys for encryption and decryption.

python3 elgamal_keygen.py

The above command allows us to generate public-key in public_key_el_gamal.txt and private-key in private_key_el_gamal.txt

elgamal_encryption.py is used to generate the ciphertext using existing plaintext and public-key.

python3 elgamal_encryption.py

The above command runs the script which reads from plain_text_el_gamal.txt to get input-text and reads the public-key from public_key_el_gamal.txt to output the cipher-text to ciphertext_elgamal.txt

elgamal_decryption.py is used to decrypt existing ciphertext using private-key and public-key.

python3 elgamal_decryption.py

The above command runs a script which reads the ciphertext from ciphertext_elgamal.txt and reads the private key from private_key_el_gamal.txt, the public-key from public_key_el_gamal.txtto output the deciphered text in decipher_elgamal.txt

The file elgamal_runtime.txt stores the running time of the program elgamal_keygen.py, which comes out to be 5.5s on average.

File description

elgamal_keygen.py

def check_prime(number): ''' checks whether a number is prime or not
by using the miller-rabin optimality test, Is performed multiple times
 because the test isn't foolproof'''
#Sources referred: Wikipedia.org, Brilliant.org

def modular_exp(a,n,number): ''' Does exponentiation and 
takes mod at the same time,i.e doesn't compute the 
exponent and operates using modulo at the last stage , instead
it does both at the same moment such that the sqauring happens
 after a mod operation has already occurred. '''
#Sources referred: wikipedia.org

def modular_inverse(m,n):'''Calculates the inverse of a number m, given modulo n 
using the extended eucledian algorithm . The extended eucledian algorithm
allows us to find x,y such that mx + ny = 1 where x turns out to be our 
modulo inverse.
 '''
#Sources referred: Wikipedia.org

def generate_primes(n,k):''' Generate n bit random numbers, and checks whether 
its prime, if not. it keeps generating until it gets the desired number of 
primes specified by the user

def gcd(a,b):''' Finds the gcd of two numbers '''

def lucas_test(g,p,q):''' Lucas test allows us to check the validity of
a 'potential' primitive root, it checks with the divisors of a given prime q.
As the q is defined to 2p+1 for our case, we just need to check with the 
divisors 2 and p '''

def find_primitive_root(q):''' Finds a primitive root for a give prime q,
in this function we generate a random number in range(q-1) and check its 
validity of being a primitive root using the Lucas test'''

elgamal_encryption.py

def encrypt(pk,text):''' encrypts the text using public keys'''

elgamal_decryption.py

def decrypt(c1,c2,a,q):''' decrypts the text using private,public keys'''

RSA

The files included in this project are: keygen_rsa.py
encrypt_rsa.py decrypt_rsa.py public_key_rsa.txt private_key_rsa.txt plaintext_rsa.txt cipher_text_rsa.txt deciphered_rsa.txt rsa_runtime.txt

File usage:

keygen_rsa.py is used to generate the public and private keys for encryption and decryption.

python3 keygen_rsa.py

The above command allows us to generate public-key in public_key_rsa.txt and private-key in private_key_rsa.txt

encrypt_rsa.py is used to generate the ciphertext using existing plaintext and public-key.

python3 encrypt_rsa.py

The above command runs the script which reads from plaintext_rsa.txt to get input-text and reads the public-key from public_key_rsa.txt to output the cipher-text to cipher_text_rsa.txt

decrypt_rsa.py is used to decrypt existing ciphertext using private-key and public-key.

python3 decrypt_rsa.py

The above command runs a script which reads the ciphertext from cipher_text_rsa.txt and reads the private key from private_key_rsa.txt, the public-key from public_key_rsa.txtto output the deciphered text in deciphered_rsa.txt

The file rsa_runtime.txt stores the running time of the program keygen_rsa.py, which comes out to be 1.5s on average.

File description

keygen_rsa.py

def check_prime(number): ''' checks whether a number is prime or not
by using the miller-rabin optimality test, Is performed multiple times
 because the test isn't foolproof'''
#Sources referred: Wikipedia.org, Brilliant.org

def modular_exp(a,n,number): ''' Does exponentiation and 
takes mod at the same time,i.e doesn't compute the 
exponent and operates using modulo at the last stage , instead
it does both at the same moment such that the sqauring happens
 after a mod operation has already occurred. '''
#Sources referred: wikipedia.org

def modular_inverse(m,n):'''Calculates the inverse of a number m, given modulo n 
using the extended eucledian algorithm . The extended eucledian algorithm
allows us to find x,y such that mx + ny = 1 where x turns out to be our 
modulo inverse.
 '''
#Sources referred: Wikipedia.org

def generate_primes(n,k):''' Generate n bit random numbers, and checks whether 
its prime, if not. it keeps generating until it gets the desired number of 
primes specified by the user

def gcd(a,b):''' Finds the gcd of two numbers '''

encrypt_rsa.py

def encrypt():''' encrypts the text using public keys'''

decrypt_rsa.py

def decrypt():''' decrypts the text using private,public keys'''

License

MIT