A simple file encryption desktop application built for study and experimentation. It allows users to encrypt and decrypt files using AES-GCM encryption with secure key derivation through the Scrypt algorithm.

Cryptography

Algorithms

• Encryption: AES-256
• Mode: GCM (Galois/Counter Mode)
• Key Derivation: Scrypt

Process

1. Key Derivation

   • A key is derived from the user password using Scrypt
   • Parameters: N=16384, r=8, p=1
   • A random 32-byte salt is generated per operation

2. Encryption (AES-GCM)

   • A random 16-byte nonce is generated
   • The file is encrypted using AES-256-GCM
   • GCM provides confidentiality and integrity via a 16-byte authentication tag

3. Encrypted File Format

   [32 bytes Salt][16 bytes Nonce][Encrypted Data][16 bytes Auth Tag]
   

4. Decryption

   • Salt and nonce are read from the encrypted file
   • The key is derived again from the password and salt
   • The authentication tag is verified before decryption

Tech Stack

• Python 3
• Flet
• PyCryptodome

Usage

Install

git clone https://github.com/devyasminn/secret-keeper.git
cd secret-keeper
pip install -r requirements.txt

Run

python run.py

Preview.mp4