File Encryption
Encrypt any file using another file as the key. It's like locking something with a physical key — except the key is a file on your computer.
The Basic Idea
Normally when you encrypt something, you use a password. You type in "MyPassword123" and your file gets locked. But passwords are easy to guess, and they're just text you remember.
This tool does it differently. You pick ANY file as your key. A photo, a random document, your favorite song — literally anything. You encrypt your secret file using that key file, and now you need BOTH files to unlock it. The key file is like a physical keycard. You can't decrypt without it.
How It Works
Step 1: Pick Your Files
You upload the file you want to encrypt (the secret) and another file to use as the key. The key file can be literally anything — a picture of your cat, a PDF, an MP3. Size doesn't matter.
Step 2: The Encryption Magic
Here's what happens behind the scenes: The tool reads your key file and converts it into raw bytes (just the digital data inside it). Those bytes become the encryption algorithm's input. It then uses those bytes to scramble your secret file in a way that's mathematically impossible to reverse without the exact same key file.
Step 3: You Get An Encrypted File
Your secret file is now gibberish. Just random bytes. Even if someone gets this encrypted file, they can't do anything with it. It looks like corrupted data.
Step 4: Decryption (When You Need It)
To get your file back, you upload the encrypted file AND the same key file. The tool reads the key file again (into bytes again), and uses it to reverse the encryption. The original file comes back, untouched.
Why This Matters: The Keystore Analogy
Think about crypto wallets. In crypto, you have a private key (a file or phrase) that you use to sign transactions and prove you own your crypto. That private key is like a digital fingerprint — it's unique to you and impossible to forge.
A keystore is basically that private key, but encrypted and locked away. If your keystore is encrypted with another password or file, even if someone steals the keystore file, they can't use the private key inside without decrypting it first.
This file encryption tool does the same thing. Your secret file is like a private key — you're wrapping it in layers of encryption using another file as the lock. Only someone with the key file can unwrap it.
Real-World Example
Scenario: You have a spreadsheet with sensitive financial data.
Key file: You pick a random image from your photos — say, a beach picture from your vacation.
Encrypt: You run this tool. It reads the beach image (converts it to bytes), uses those bytes to scramble your spreadsheet into complete gibberish.
Result: Encrypted file that looks like corruption. The beach image sits in your photos library, innocently.
Later: You want your data back. You upload the encrypted file and the beach image again. The tool reads the beach image's bytes, reverses the encryption, and your spreadsheet is restored.
The Tech
Algorithm: AES-256-GCM (Industry standard) Key Derivation: PBKDF2 or Argon2 Key Source: Raw file bytes Process: 1. Read key file → extract bytes 2. Generate encryption key from those bytes 3. Use key to encrypt secret file with AES-256 4. Append authentication tag (ensures integrity) Decryption requires: 1. Exact same key file (byte-for-byte) 2. Exact encrypted file
Under the hood, this uses AES-256-GCM, the same encryption standard used by governments and banks. The strength is that the key is derived from file bytes, making it practically unbreakable without the exact key file.
The authentication tag ensures the file hasn't been tampered with. If someone modifies even one byte of the encrypted file, decryption will fail.
⚠️ Important
- • You MUST keep the key file safe. Lose it, and your encrypted file is permanently locked.
- • Don't modify the key file. Even changing one byte makes it useless for decryption.
- • Store key files separately from encrypted files (different locations, different drives).
- • This is NOT a replacement for secure file sharing. It's local encryption.