Usage

Package usage

To encrypt a message, use the following code, available in the examples directory of the package:

import pyaescbc

# Encryption
cleardata = bytearray("Hello, World!", 'utf-8')
pin = bytearray("1234", 'utf-8')
password = bytearray("password", 'utf-8')
iterations = pyaescbc.generate_pin_iterations(pin, delete_keys=True)
authdata = bytearray("user=toto", 'utf-8') # Optional authentication data (can be None)
encrypted_bundle = pyaescbc.encrypt(cleardata, password, iterations, authdata=authdata, delete_keys=True)

# Decryption
pin = bytearray("1234", 'utf-8')
password = bytearray("password", 'utf-8')
iterations = pyaescbc.generate_pin_iterations(pin, delete_keys=True)
authdata = bytearray("user=toto", 'utf-8') # Optional authentication data (can be None)
decrypted_data = pyaescbc.decrypt(encrypted_bundle, password, iterations, authdata=authdata, delete_keys=True)

print(decrypted_data)

The iteration can also be generated randomly, using pyaescbc.generate_random_iterations().

Type convertion

If your clear data is a string, you can convert them to bytearray using the following code:

# Convert a string to bytearray
string = "Hello, World!"
byte_array = bytearray(string, 'utf-8')

Similarly, after decrypting, you can convert the bytearray back to a string using the following code:

# Convert a bytearray to string
decrypted_string = byte_array.decode('utf-8')
print(decrypted_string)  # Output: Hello, World!

For encrypted data (ie the encrypted_bundle), the type is a bytearray but it can’t be converted to a string using utf-8. This is because the encrypted data is not a valid UTF-8 string.

I recommend to save the encrypted data in a file or a database as a bytearray, and then read it back as a bytearray when you need to decrypt it.

Otherwise, you can convert the bytearray to a base64 string using the following code:

import base64

# Convert bytearray to base64 string
encrypted_bundle = bytearray(b'\x00\x01\x02\x03')
base64_string = base64.b64encode(encrypted_bundle).decode('utf-8')
print(base64_string)

The base64 string can be saved in a file or a database as a string, and then read it back as a base64 string when you need to decrypt it. To reconvert the base64 string to a bytearray, you can use the following code:

# Convert base64 string to bytearray
base64_string = "AAECAw=="
encrypted_bundle = bytearray(base64.b64decode(base64_string))
print(encrypted_bundle)