cryptoran

Pure python3 crypto library implemented from scratch

Cryptoran provides pure Python 3 implementations of various cryptosystems and protocols along with mathematical tools used to build them. No external dependencies!

why use cryptoran

Cryptoran aims to be a very easy tool to use; providing cryptographic primitives and protocols. A possible use case is to providing security to your client-server application [example project: pigeon]. An addition of few lines of code will provide security [see notes] to your communication.

Getting Started

Install easily with pip:

$ pip3 install cryptoran

Command line toolkit

You can use the command line toolkit as cryptoran command [<args>].

Example

$ cryptoran aes cbc myfile.txt -e
Encryption result written to myfile.txt.enc
Key stored in myfile.txt.key

$ cryptoran aes cbc myfile.txt -d -k myfile.txt.key
Output written to myfile.txt.enc.dec

Yeah, the filename extensions doesn't seem good. Perhaps you have a great proposal on that; feel free to contribute!

Python 3 package

Import the package and retrieve the module you want.

from cryptoran import blockcihper

plaintext = "some ASCII encoded string"
key = 0x89031375397e64eb86ed7d2f924e3100
iv = 0xd0513d87e0be764b41ebb459680485e8

cipher = blockcipher.AES('cbc', key, iv)
ciphertextBlocks = cipher.encrypt(plaintext)
# [0xdf87af9efc6747b7e4c4f6bd1ae46161, 0xaa6dce569cc53c272f6b9303e49d1c4b]

print(cipher.decrypt(ciphertextBlocks)) # this is an ASCII encoded string

A concise documentation will be provided in subsequent updates. Proper unit tests haven't been developed yet, version 0.1 will cover them.

Features

• Block ciphers
  Block ciphers support CBC and ECB modes of operations.
  • AES
  • DES
• Public key crypto
  Optional support RSA-OAEP is available.
  • RSA
  • Elgamal
• Key exchange
  • Diffie-Hellman protocol
• Signatures
  • RSA signature

Known Vulnerabilities

• Python's random library was used for PRNG, it uses linear congruential generators which are known to be cryptographically insecure. The secrets module was introduced in Python 3.6 which is claimed to be a module capable of generating cryptographically secure random numbers. Migration to this module will be done soon.

• Diffie-Hellman implementation does not check for the group order; hence it is vulnerable against the small subgroup confinement attack

• CBC mode of operation is vulnerable against padding oracle attacks.

Notes

These implementations are intended for educational purposes only, they are NOT cryptographically secure and they are probably vulnerable against side-channel attacks, some MITM and more.