PQCryptography

This library was written due to rising threat of quantum computing. It main goal is to create easy wrapper of liboqs to spread post quantum cryptography

Installation

pip install pqcryptography

How to use pqcryptography

Importing

import pqcryptography as pqc

Generating keys / signs

public_key, private_key = pqc.encryption.generate_keypair()
public_sign, private_sign = pqc.signing.generate_signs()

Just like in any other asymmetric encryption library.

Encryption and decryption

How encryption work

message = "Test Message"
encrypted_message = pqc.encryption.encrypt(public_key, message.encode("utf-8"))

Please take into consideration that message needs to be encoded before encryption. Here I used utf-8 encoding. Alternatively you can use raw bytes for message. Also encryption of message increases its size depending on algorithm. You can get this length of ciphertext using pqc.encryption.get_details(algorithm = "{algorithm that you use}"). encrypted_message type is bytes. How decryption work

retrieved_message = pqc.encryption.decrypt(private_key, encrypted_message)
print(retrieved_message.decode("utf-8"))

retrieved_message needs to be decoded if you didn't encrypt raw bytes. Output is "Test Message"

Ciphers

You can create ciphers to improve performance. It should be used for sockets and stuff alike.

client_cipher, ciphertext = pqc.encryption.create_cipher(public_key) #ciphertext should be sent to client
server_cipher = pqc.encryption.decrypt_cipher(private_key, ciphertext)
print(server_cipher.decrypt(client_cipher.encrypt(message.encode('utf-8'))))
print(client_cipher.decrypt(server_cipher.encrypt(message.encode('utf-8'))))

Signing and verifying

How signing works

signed_message = pqc.signing.sign(private_sign, message.encode("utf-8"))

signed_message type is bytes. Signature is appended to the message and its size will vary from algorithm to algorithm. Here's how to get it's size:

print(pqc.signing.get_details()["length_signature"])

How verification works So we got our message. That is how we should verify that it is legit:

verified_message = pqc.signing.verify(public_sign, signed_message)
print(verified_message.decode("utf-8"))

verified_message is just encoded message with signature stripped. If message was tampered with verify function will raise AssertionError

Using non-default algorithm

So you want to change encryption/signing algorithm? Sure! Just use keyword algorithm. It is supported for every function except get_algorithms()

Default algorithms

Default encryption algorithm is Kyber1024. Default signing algorithm is Dilithium5

Algorithms

If you don't want to use default algorithm you can pick one from the algorithm list.

print(pqc.encryption.get_algorithms())
print(pqc.signing.get_algorithms())

Note: Results are incomplete and probably outdated. You should run the code yourself

['BIKE-L1', 'BIKE-L3', ..., 'FrodoKEM-1344-AES', 'FrodoKEM-1344-SHAKE']
['Dilithium2', 'Dilithium3', ..., 'SPHINCS+-SHAKE-256f-simple', 'SPHINCS+-SHAKE-256s-simple']

so you don't trust me bro?

This package uses unofficial liboqs python package which is shipped with precompiled oqs libraries. You can not be certain that those binaries aren't malicious so you want to build your own. You can build binaries by following build instructions at oqs official repository and replace .so/.dll files in the package folder (python_directory/site-packages/liboqs/).

Im using pyinstaller / nuitka and it doesnt work

Just copy .so/.dll files from liboqs package folder (python_directory/site-packages/liboqs/) to your executable folder and it will load files from your local directory.