Can OnlyFiles or an attacker decrypt my file without the password?

No. We use standard AES-256-GCM encryption with 250,000 PBKDF2 iterations. Without your exact password, the encrypted file is mathematically indistinguishable from random noise.

How does the recipient decrypt the file?

Send the encrypted .enc file to your recipient via email or message. They can visit onlyfiles.in, drop the .enc file into the Decrypt tool, enter the password you shared with them, and save the original file.

Home/Security Vault

Zero-Knowledge · Web Crypto API

In-Browser File Encryption (AES-256-GCM)

Password-protect any file locally using military-grade AES-256-GCM cryptography. Your password and data are never sent to OnlyFiles or any server.

Drop any file here to encrypt

PDF, image, video, spreadsheet, or archive.

How OnlyFiles Zero-Knowledge Encryption Works

Most file-sharing services that offer password protection perform encryption on their servers, which means they hold the keys and can decrypt your files on request or suffer catastrophic server-side leaks.

OnlyFiles operates on a true Zero-Knowledge model: We use the browser's native, hardware-accelerated window.crypto.subtle API. When you supply a password:

1. A random 16-byte salt is generated via cryptographically secure random values.

2. Your password is stretched into a 256-bit encryption key using PBKDF2 with 250,000 SHA-256 rounds.

3. The file is encrypted using AES-GCM with a fresh 12-byte initialization vector (IV), providing both privacy and tamper-proof authentication.

Mathematically Unbreakable

AES-256 is the standard trusted by security agencies and banks globally. Brute forcing is computationally impossible.

Zero-Knowledge Design

We never see your password, key, or unencrypted file bytes. If subpoenaed, we have nothing to provide.

Frequently Asked Questions

What happens if I forget the password?

Because OnlyFiles never stores your password or retains a master key, forgotten passwords cannot be recovered. Ensure you remember or safely record your passphrase.

How does the recipient decrypt the document?

They simply open OnlyFiles, drag the .enc file into the Decrypt tool on the homepage, and enter the password you provided. The original file is restored instantly in their browser without an account.