rsa-crypto.py

import rsa
import base64
  
def split_len(seq, length):
    return [seq[i:i+length] for i in range(0, len(seq), length)]
    
def encrypt(text, pub_key):
    block_size = rsa.common.byte_size(pub_key.n) - 11
    encrypted = ""
    for part in split_len(text, block_size):
        encrypted += rsa.encrypt(part, pub_key)
    return encrypted
  
def encrypt_str(text, pub_key, encode=base64.standard_b64encode):
    return encode(encrypt(text, pub_key))
  
def decrypt(encrypted, pri_key):
    block_size = rsa.common.byte_size(pri_key.n)
    text = ""
    for part in split_len(encrypted, block_size):
        text += rsa.decrypt(part, pri_key)
    return text
  
def decrypt_str(text, pub_key, decode=base64.standard_b64decode):
    return decrypt(decode(text), pub_key)
  
def export_key(key):
    return key.save_pkcs1()
  
def export_key_file(key, path):
    file(path, "w").write(export_key(key))
  
def load_key(key_str):
    if "-----BEGIN RSA PRIVATE KEY-----" in key_str:
        return rsa.PrivateKey.load_pkcs1(key_str)
    else:
        return rsa.PublicKey.load_pkcs1(key_str)
  
def load_key_file(path):
    return load_key(file(path).read())
    
    
if __name__ == '__main__':
    message = 'hello world.'
    #
    with open('public.pem') as f:
        pub_key = load_key(f.read())
    encrypted_data = encrypt_str(message, pub_key)
    #
    with open('private.pem') as f:
        pri_key = load_key(f.read())
    data = decrypt_str(encrypted_data, pri_key)