chafe

A CHAcha File Encryptor

This Python package provides tools for encrypting and decrypting files with Daniel Bernstein's ChaCha20 stream cipher, using a key derived from a pass phrase. Encrypted files include a Poly1305 authentication tag to detect tampering with an encrypted file.

Warning

This is still a work in progress, published here for testing only. Do not use it for anything important. The file formats and encryption algorithms are subject to change, which could leave you with encrypted files that you cannot decrypt.

Installation

Install this package with pip:

python3 -m pip install --pre chafe

The pypi package name is "chafe". The python module installed with this command is named "chacha". The --pre option is needed because the current version of this package is a pre-release.

Usage

The package provides two entry points named encrypt and decrypt. That means that if this module is in your Python path then the module can be used as follows:

To encrypt a file named myfile:

% python3 -m chacha.encrypt myfile

You will be prompted for a password, and an encrypted file named myfile.cha will be created. The password will be visible until the encryption is finished, then erased. (So write it down on a piece of paper before it disappears!) Note that the erasure uses ANSI escape sequences which will not work correctly if the terminal window is too narrow.

To decrypt myfile.cha:

% python3 -m chacha.decrypt myfile.cha

You will be prompted for the password, and a decrypted file named myfile will be created. The password will be visible until the decryption is finished, then erased.

If you install this module with pip and have configured your path to make your pip-installed scripts available, then the commands will simply be:

% chacha-encrypt myfile

and

% chacha-decrypt myfile.cha