securefilecrypt 0.1.4

Secure File Encryption Library

securefilecrypt — Simple AES-GCM File Encryption

SecureFileCrypt is a Python utility for encrypting and decrypting files using AES-256-GCM with password-based key derivation (PBKDF2-HMAC-SHA256).
It is designed for ease of use while providing strong, modern encryption with authentication to ensure data confidentiality and integrity.

Features

• AES-256 in Galois/Counter Mode (GCM) for authenticated encryption
• Password-based key derivation using PBKDF2-HMAC-SHA256 with configurable iterations
• Random salt and nonce generated for each encryption
• Automatic salt length derived from password characteristics
• Simple file-based workflow: encrypt and decrypt with one function call
• Compatible across Python 3.6+ on Windows, Linux, and macOS

Security Design

• Encryption algorithm: AES-256-GCM (confidentiality + authentication)
• Key derivation: PBKDF2-HMAC-SHA256, 100,000 iterations
• Salt: Random per file, length based on password contents
• Nonce: 12 bytes random per encryption
• Password requirements: At least 12 base36 characters (0-9a-z)

Installation

pip install securefilecrypt

Quick Start

Encrypt a file

from securefilecrypt import EncryptFile

status, message = EncryptFile("secret.txt", "secret.enc", "mypassword123abc")
if not status:
  print("Error:", message)
else:
  print("File encrypted successfully!")

Decrypt a file

from securefilecrypt import DecryptFile

status, message = DecryptFile("secret.enc", "secret_decrypted.txt", "mypassword123abc")
if not status:
  print("Error:", message)
else:
  print("File decrypted successfully!")

Command line tool

On the command line the library can be called with the following arguments:

Usage: sfcrypt <input_file> <output_file> (--encrypt|--decrypt) (--pw:<password>|--ev:<envvar>)

<input_filename>  : Input file for encryption or decryption

<output_filename> : Encrypted / decrypted file to produce

--encrypt           : Encryption mode

--decrypt           : Decryption mode

--pw:<password>   : Password for encryption/decription

--ev:<envvar>     : Get password for encryption / decryption from an environment variable

API Reference

EncryptData(input_file, password)

Encrypts input_file using AES-256-GCM with provided password. Returns:

• `status' (bool): True if successful, False something went wrong
• message (str): Error message in case of error, otherwise empty
• data (bytes): Encrypted bytes

DecryptData(input_file, password)

Decrypts input_file using AES-256-GCM with provided password. Returns:

• `status' (bool): True if successful, False something went wrong
• message (str): Error message in case of error, otherwise empty
• data (bytes): Decrypted bytes

EncryptFile(input_file, output_file, password)

Encrypts input_file into output_file using AES-256-GCM with provided password. Returns:

• `status' (bool): True if successful, False something went wrong
• message (str): Error message in case of error, otherwise empty

DecryptFile(input_file, output_file, password)

Decrypts input_file into output_file using AES-256-GCM with provided password. Returns:

• `status' (bool): True if successful, False something went wrong
• message (str): Error message in case of error, otherwise empty

Security Notes

• Always use a strong password (long, random, mix of letters/numbers).
• Store your password securely — if lost, data cannot be recovered.
• PBKDF2 is secure, but for higher resistance to GPU cracking, consider upgrading to Argon2id in the future.

License

MIT License — do anything with it, but no warranty.

Changelog