PCS - P7MJ's enCryption System

Version: A-1-i Proto
Author: P7MJ

PCS is a lightweight, secure Python utility designed to encrypt and decrypt ZIP files (and other binary data) using industry-standard AES-256 encryption via the Fernet protocol.

🚀 Features

Hardened Key Derivation: Uses PBKDF2HMAC with 480,000 iterations to turn your password into a cryptographically strong key.
Salted Encryption: Generates a unique 16-byte random salt for every encryption process, protecting against rainbow table attacks.
Embedded Metadata: The salt is stored directly inside the encrypted file (.p7c_enc), so you only need your password to decrypt.
Authenticated Encryption: Uses Fernet, which ensures that if the file is tampered with or the password is wrong, the system will refuse to decrypt rather than producing corrupted data.
User Safety: Includes file existence verification and optional "shredding" (deletion) of source files after processing.

🛠️ Installation

PCS requires Python 3.x and the cryptography library.

Clone or download this repository.
Install the dependency:
```
pip install cryptography
```

📖 How to Use

Run the script using:

python PCS-A-1-i-Proto.py

1. Encrypting a File

Select option [1].
Enter the name of your .zip file (the script automatically appends the extension).
Create a password. Important: If you lose this password, your data is unrecoverable.
The script creates a file with the .p7c_enc extension.
Choose whether to "shred" (permanently delete) the original file.

2. Decrypting a File

Select option [2].
Enter the full name of the .p7c_enc file.
Enter your password.
The file will be restored as unencrypted.zip.

⚠️ Important Security Notes

Password Length: While the script is technically secure, the strength of the encryption relies entirely on the complexity of your password.
The Salt: The first 16 bytes of your .p7c_enc file is the salt. Do not modify or "trim" the encrypted file, or it will become undecryptable.
Permanent Deletion: The "shred" feature uses os.remove(), which bypasses the Recycle Bin/Trash on most systems. Use with caution!

🏗️ Technical Details

Encryption Engine: AES-128 in CBC mode with PKCS7 padding.
Authentication: HMAC using SHA256.
KDF: PBKDF2 with SHA256.