Python file encryptor Gitmodule

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About

This encryptor provides two options of encryption:

• (with salt) generate salt based on the key provided by you, then encrypt files using that salt
• (without salt) encrypt files using your key

It optionally provides an option (if salt is used):

• to save the salt to a file

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Technical Overview of FileEncryptor

FileEncryptor is a class designed to handle the encryption and decryption of files using symmetric encryption (Fernet). It uses the cryptography library for encryption and key derivation, with support for both salt-based and master key-based encryption.

Key Features:

1. Encryption Mechanism:

   • Uses the cryptography.fernet.Fernet class for AES encryption.
   • For key generation, it supports two modes:
     • With Salt: Derives the key using PBKDF2-HMAC with SHA-256 and a salt.
     • Without Salt: Uses a master key directly, truncated/padded to 32 bytes.

2. Modes:

   • Encrypt: Reads files, encrypts them using the derived or provided key, and stores the encrypted data with a .enc extension. The original file is deleted after encryption.
   • Decrypt: Decrypts files with the .enc extension using the stored key, restores the original file, and deletes the encrypted file.

Key Operations:

• Encryption: Generates a secure key (either from PBKDF2 with salt or a provided master key) and encrypts the file's content.
• Decryption: Decrypts files using the same key and restores the original content.

Dependencies:

• cryptography.fernet.Fernet for encryption.
• PBKDF2-HMAC for key derivation when using salt.
• BinaryFileManager interface for file handling (read/write/delete).

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Usage

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• Usage with not_gitmodules (recommended)

  • What's not_gimodules ?

1. First of all, this module requires another module: FileManager

Open not_gitmodules.yaml file and add it, alongside with this module, example:

file_manager : https://github.com/Armen-Jean-Andreasian/notgitmodules-file-manager
file_encryptor : https://github.com/Armen-Jean-Andreasian/notgitmodules-file-encryptor-py

2. Update Not Gitmodules, example:

pip install -r from my_gitmodules/requirements.txt

3. Install the library dependencies

pip install -r from my_gitmodules.requirements.txt

or manually include

cryptography~=44.0.0 to your requirements.txt

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• Usage with gitmodules

For gitmodules, follow the usual steps to add the repository as a submodule to your project and use it as needed.

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3. Initialize FileManager class and pass it to FileEncryptor

from my_gitmodules.file_encryptor import FileEncryptor
from my_gitmodules.file_manager_module import BinaryFileManager

bin_manager = BinaryFileManager()

file_encryptor = FileEncryptor(
    binary_file_manager=bin_manager,
    files_to_encode=[
        '.env', 'some_file.txt'
    ],
    use_salt=True,
    save_salt=True,
    salt_file_name='playground/salt',
    delete_original_file=False
)

file_encryptor.encrypt() # to encrypt file(s)
file_encryptor.decrypt() # to decrypt file(s)

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Docker: Important note

You need to provide the key through input() function, so the Docker container should be run interactively (i.e., with the -it flag).

The -it flag ensures that the container is interactive and connected to the terminal, allowing the user to provide input directly.

Here’s a scenario:

1. Dockerfile Example

FROM python:3.9-slim

WORKDIR /app
COPY . /app

RUN pip install -r requirements.txt

CMD ["python", "file.py"]

2. docker-compose.yml Example

version: '3'
services:
  myapp:
    build: .
    stdin_open: true
    tty: true

3. Running the Container

With the -it flag, you can run the container interactively:

docker run -it myapp

Or, if using Docker Compose:

docker-compose run myapp

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Some examples

from my_gitmodules.file_encryptor import FileEncryptor
from my_gitmodules.file_manager_module import BinaryFileManager

bin_manager = BinaryFileManager()


def encryptor_with_salt():
    return FileEncryptor(
        binary_file_manager=bin_manager,
        files_to_encode=[
            'file1.txt',
        ],
        use_salt=True,
        save_salt=True,
        salt_file_name='salt'
    )


def encryptor_without_salt():
    return FileEncryptor(
        binary_file_manager=bin_manager,
        files_to_encode=[
            'file2.txt',
        ],
        use_salt=True,
        save_salt=True,
        salt_file_name='salt'
    )


s_encryptor = encryptor_with_salt()

s_encryptor.encrypt()
s_encryptor.decrypt()

encryptor = encryptor_without_salt()
encryptor.encrypt()
encryptor.decrypt()