redacted-py

Redacting classified documents

This repository holds the code base for my redacted-py library in Python.
It is mainly based off my Feistel cipher for Format-Preserving Encryption to which I added a few tools to handle document, database and file manipulation to ease out the operation.

Motivation

In some fields (like healthcare for instance), protecting the privacy of data whilst being able to conduct in-depth studies is both vital and mandatory. Redacting documents and databases is therefore the obligatory passage. With redacted-py, I provide a simple yet secure tool to help redacting documents based on either a dictionary, a record layout or a tag to decide which parts should actually be redacted.

Usage

You can use either a dictionary or a tag (or both) to identify the words you want to redact in a document. The tag should be placed before any word that should be redacted. The default tag is the tilde character (~).

For example, the following sentence will only see the word tagged redacted: "This is a ~tagged sentence".

$ pip install redacted-py

from redacted import DefaultRedactor, Dictionary
from feistel import FPECipher, SHA_256

source = "Some text ~tagged or using words in a dictionary"

cipher = FPECipher(SHA_256, key, 10)
redactor = DefaultRedactor(cipher)
redacted = redactor.redact(source)

expanded = redactor.expand(redacted)
assert expanded == source, "Original data should equal ciphered then deciphered data"

cleansed = redactor.clean(expanded)
assert cleansed == "Some text tagged or using words in a dictionary", "Cleaning should remove any tag mark"

You may also use it in the console with the following command line instructions:

usage: python3 -m redacted [-h] [-b | --both | --no-both] [-d DICTIONARY] [-H HASH] [-i INPUT] [-k KEY] [-o OUTPUT] [-r ROUNDS] [-t TAG] [-x | --expand | --no-expand]

options:
  -h, --help            show this help message and exit
  -b, --both, --no-both
                        Add to use both dictionary and tag
  -d DICTIONARY, --dictionary DICTIONARY
                        The optional path to the dictionary of words to redact
  -H HASH, --hash HASH  The hash engine for the round function [default sha-256]
  -i INPUT, --input INPUT
                        The path to the document to be redacted
  -k KEY, --key KEY     The optional key for the FPE scheme (leave it empty to use default)
  -o OUTPUT, --output OUTPUT
                        The name of the output file
  -r ROUNDS, --rounds ROUNDS
                        The number of rounds for the Feistel cipher [default 10]
  -t TAG, --tag TAG     The optional tag that prefixes words to redact [default ~]
  -x, --expand, --no-expand
                        Add to expand a redacted document

Tests

$ git clone https://github.com/cyrildever/redacted.git
$ cd redacted/py/
$ pip install -e .
$ python3 -m unittest discover

License

The use of the redacted libraries and executables are subject to fees for commercial purpose and to the respect of the BSD-2-Clause-Patent license.
Please contact me to get further information.

NB: It is still under development so use in production at your own risk for now.