Skip to content

documentation.md

Latest commit

 

History

History
103 lines (84 loc) · 2.71 KB

documentation.md

File metadata and controls

103 lines (84 loc) · 2.71 KB

Documentation

To use LC4, first import the lc4 module.

>>> import lc4

Encryption and Decryption

Text is encrypted with lc4.encrypt.

>>> import lc4
>>> key = "#qiye7hozcb2asm5kd9x_nlvrwput6f3j84g"
>>> nonce = "mi2zwe"
>>> text = "this_is_an_example"
>>> encrypted = lc4.encrypt(key, text, nonce=nonce)

Text is decrypted with lc4.decrypt.

>>> decrypted = lc4.decrypt(key, encrypted, nonce=nonce)

lc4.encrypt and lc4.decrypt both take the following arguments:

  • key A secret permutation of the characters in the alphabet (see documentation for alphabet below). A key can be randonly generated using the command-line utility (see Interactive Command-Line Utility documentation below).
  • text Text to be encrypted/decrypted.
  • nonce (optional) A sequence of randomly chosen characters from the alphabet. The paper specifies that nonces be 6 or more characters and different for each message. A nonce can be randonly generated using the command-line utility (see Interactive Command-Line Utility documentation below).
  • alphabet (optional; defaults to "#_23456789abcdefghijklmnopqrstuvwxyz") A string of 36 unique characters that comprise messages.
  • verbose (optional; defaults to False) A boolean indicating whether there should be status logging to stdout.

Interactive Command-Line Utility

The lc4 package includes an interactive command line utility. This can be used to generate nonces, generate keys, and encrypt/decrypt text.

Example session
$ lc4 --version
lc4 0.1.3

$ lc4 --help
usage: lc4.py [-h] [-a STRING] [-n INTEGER]

optional arguments:
  -h, --help            show this help message and exit
  --version             show program's version number and exit
  -a STRING, --alphabet STRING
                        A string of 36 characters representing the alphabet.
                        (default: #_23456789abcdefghijklmnopqrstuvwxyz)
  -n INTEGER, --nonce-length INTEGER
                        The number of characters in randomly generated nonces
                        when using option 2. (default: 6)
  --verbose             Enables status logging to stdout. (default: False)

$ lc4
1. Generate Key
2. Generate Nonce
3. Encrypt
4. Decrypt
5. Quit
>>> 1
#qiye7hozcb2asm5kd9x_nlvrwput6f3j84g

$ lc4
1. Generate Key
2. Generate Nonce
3. Encrypt
4. Decrypt
5. Quit
>>> 2
mi2zwe

$ lc4
1. Generate Key
2. Generate Nonce
3. Encrypt
4. Decrypt
5. Quit
>>> 3
Key: #qiye7hozcb2asm5kd9x_nlvrwput6f3j84g
Nonce: mi2zwe
Text: this_is_an_example
emt9lnk8gg7#3h7s8k

$ lc4
1. Generate Key
2. Generate Nonce
3. Encrypt
4. Decrypt
5. Quit
>>> 4
Key: #qiye7hozcb2asm5kd9x_nlvrwput6f3j84g
Nonce: mi2zwe
Text: emt9lnk8gg7#3h7s8k
this_is_an_example