Cryptography transforms readable data into unintelligible text so only authorised parties may restore it. File-level encryption applies this transformation to entire documents, wrapping every byte within a mathematically derived cipher-text. Decryption reverses the operation when you present the correct secret key. The tool automates both directions while remaining entirely inside your browser, avoiding external servers.
Modern browsers provide strong cryptography primitives that operate at native speed. This utility orchestrates those primitives through a lightweight reactive interface that reads selected files, derives a symmetric key from your password and chosen algorithm, then streams the result back as either plain binary or encoded text. Nothing leaves the sandboxed workspace, ensuring sensitive information never crosses the network boundary.
Use it to share sensitive project archives with teammates during remote collaboration; avoid reusing weak passwords.
Technical Details:
Incoming files are read as ArrayBuffers and chunked into manageable blocks before encryption or decryption. A password-based key-derivation routine hashes the supplied secret, trimming the digest to the required length for each cipher. Depending on the algorithm, a random nonce or initialization vector is prepended so the output can be safely reversed later.
Completed data streams are downloaded through an object-URL tied to a short-lived Blob, sidestepping traditional network transfers. Optional preview generation displays the first 160 encoded characters, letting you confirm correctness before saving. All temporary objects are released when the page unloads, eliminating residual traces on disk or memory.
Drag-and-Drop Input
Drop files onto the highlighted zone or click to browse, instantly loading them into the local processing pipeline without size limits imposed by remote services.
Algorithm Selector
Choose from multiple symmetric ciphers and key lengths; the interface adapts required parameters and warns when a browser feature cannot support a selected mode.
Password-Based Key Derivation
A SHA-256 digest of your password plus optional salt produces a fixed-length key, ensuring consistent decryption across sessions regardless of original password length.
Advanced Parameters
Reveal an expandable panel to generate random nonces or salts, switch between base-64 and hexadecimal encodings, and copy a short preview for quick verification.
Instant Download
After processing, a signed Blob URL becomes a single-click download button, naming the file with .enc or removing it when successfully restored.
Step-by-Step Guide:
Follow these steps to encrypt or decrypt a document quickly.
- Click the Drag & drop or click to browse area or drop a file onto it.
- Select a cipher from the Algorithm dropdown list.
- Type a strong secret into the Password input.
- Choose Encrypt or Decrypt using the radio buttons.
- Press the main Encrypt / Decrypt button to start processing.
- When finished, click Download Encrypted File or Download Decrypted File to save the result.
FAQ:
Find quick answers to common questions.
Is my data stored?
No. Processing happens entirely in your browser.
Why do I see “requires HTTPS”?
Some ciphers need secure origins; use HTTPS or localhost.
Which browsers are supported?
The latest versions of major desktop and mobile browsers.
How strong is the encryption?
It matches the strength of the underlying cipher and key size.
How can I verify integrity?
Compare previews or use an external checksum after download.
Troubleshooting:
Resolve common issues quickly.
- Decryption fails immediately — ensure the password and algorithm match the original settings.
- “Requires HTTPS” message — open the page over https:// or run from localhost.
- Download button missing — check browser download permissions or pop-up blockers.
- Preview shows garbled characters — switch between Hex and Base 64 encodings.
- Large files stall — verify available memory and close other heavy tabs.
Advanced Tips:
Boost efficiency and security with these expert suggestions.
- Generate a random salt for each session to strengthen derived keys.
- Keep passwords in a dedicated manager rather than memorising them.
- Use XChaCha-based modes for longer nonces when encrypting very large files.
- Switch to hexadecimal output for easier diffing in version control.
- Clear the browser cache after processing highly sensitive material.
Glossary:
Key terms used throughout the tool.
- ArrayBuffer
- Binary container for fixed-length raw data.
- Nonce
- Number used once to randomise encryption output.
- Object-URL
- Ephemeral link to in-memory file data.
- Salt
- Random bytes added to a password before hashing.
- Symmetric Cipher
- Algorithm using the same key for encryption and decryption.