File Encryptor
Encrypt a file or a piece of text with a password, right in your browser. Nothing is ever uploaded to a server.
Everything happens in your browser, with nothing sent over the network. Your file is processed on your device only.
How to use it
To encrypt a file
- Choose the document you want to protect, or switch to the Text tab if you only have a message to encrypt.
- Generate a passphrase or a 20-character password, then copy it and save it on your device. This matters: the password cannot be recovered.
- Tick the box "I have saved my password".
- Click Encrypt. The encrypted file is saved on your device with a .tpenc extension. Above 50 MB, a dialog first asks where to write it.
- Send the encrypted file to your recipient (WhatsApp, email, a shared drive…), then give them the password through a different channel — the file by email and the password by text message, for instance.
- Send them the address of this tool as well, copied from your browser's address bar: they will need it to decrypt the file.
- When you are done, reload the page: the fields are cleared and the password no longer stays on screen.
Drop your file here
or click to browse — one file at a time
Type or generate a password.
Copy your password and store it somewhere safe. Without it the document cannot be decrypted. The password cannot be recovered.
Encrypt a file with a password — no account, no upload
Why encrypt a file before sending it?
A document sent by email, chat or a file-transfer service passes through machines you do not own: mail servers, spam filters, attachment hosts, backups. Each of those keeps a copy, sometimes for years. Encrypting the file first moves the protection: the channel no longer has to be trustworthy, because the file protects itself. A payslip, a contract, a scanned ID or an accounting export stays unreadable to anyone who gets hold of it without the password.
This tool encrypts on your side, in your browser, without sending the file over the internet: the computation happens on your machine. You can check that. Open the Network tab of your browser's developer tools while encrypting: the only requests you will see are the initial load of the tool's own scripts from toolpilot.app. Once those are in place nothing else leaves your machine, and your file is never transmitted. No account is required, no share link is minted, and no copy of your document exists anywhere but on your device.
Real-world strength comes down to two things: how good the password is, and how you send it. A file emailed with its password in the same message protects nothing. Split them: file by email, password by phone, SMS or an encrypted messenger. The built-in generator produces random passwords long enough to withstand an offline attack against the file.
Common use cases
- Sending HR or medical documents
- Payslips, employment contracts, sick notes, test results — documents that have no business sitting in plaintext in a shared mailbox or a host's backup.
- Sending records to an accountant or lawyer
- Balance sheets, bank statements, case files: encrypt the archive before uploading it to a transfer service, and give the password over the phone.
- Protecting a cloud backup
- A file encrypted before upload stays unreadable to the host and to anyone who gets into the account, including after a breach on the provider's side.
- Archiving a sensitive document on a USB stick
- Sticks get lost. An encrypted file found by a stranger is just a block of bytes.
How to encrypt a file in three steps
Drop your file into the drop zone, or switch to the Text tab to protect a short message. Any file type works. To send several documents, put them in a ZIP archive first.
Type a password and confirm it, or click Generate for a random one. The meter shows the estimated entropy, and warns below 50 bits. Then tick the confirmation box: nobody, ToolPilot included, can recover a file whose password has been lost.
Click Encrypt and download the resulting .tpenc file. Send it however you like, then pass the password along through a different channel. To decrypt, your recipient drops the file on this same page, in the Decrypt tab.
Frequently asked questions
- What happens if I lose the password?
- The file is gone for good. There is no recovery procedure, no security question, no support desk: the decryption key is computed from your password and is never stored anywhere. That is exactly what makes the scheme sound, and exactly what makes it unforgiving. Save the password in a password manager before closing the tab.
- How is this different from a password-protected ZIP?
- A ZIP encrypted with ZipCrypto — still the default in several popular tools — falls in seconds to a known-plaintext attack documented back in 1994. AES-256 ZIP is sound, but most consumer tools derive the key with a lightly configured PBKDF2, which makes offline guessing cheap. This tool uses Argon2id with 64 MiB of memory, designed to make every attempt expensive even on a GPU. A ZIP also leaves the file listing readable in the clear; here, the filename itself is encrypted.
- How large a file can I encrypt?
- Up to 50 MB in every browser. Above that the tool writes straight to disk instead of assembling the result in memory, which removes the limit — that streaming path relies on the File System Access API, available today in Chrome and Edge but not in Firefox or Safari. For several files, put them in a ZIP archive first.
- Are my files uploaded to a server?
- No, and you can check. Encryption and decryption run entirely in your browser, inside a Web Worker. Open the Network tab of your developer tools and start an encryption: the only requests are the tool's own code loading from toolpilot.app, once per visit. Not a byte of the file is transmitted. The page also enforces a Content-Security-Policy that limits `connect-src` to the site's own origin, so even injected code would have nowhere to send your data. It loads no ads and no third-party scripts, unlike the rest of the site.
- Which algorithms does it use?
- The key is derived from the password with Argon2id at 64 MiB of memory, 3 iterations and 4 lanes — the second recommended option in RFC 9106, above the OWASP minimum. The content is then encrypted with AES-256-GCM in 1 MiB blocks, each carrying its own authentication tag, with the block number in the nonce and a flag on the final block. That construction, borrowed from the age format, means a block cannot be removed, duplicated or reordered without decryption failing. The full format specification is published in the site's repository.
- What does this tool not protect against?
- A weak password, or one sent through the same channel as the file. A device already compromised by malware or a hostile browser extension, which would see the file before it is encrypted. A compromise of toolpilot.app serving modified JavaScript — which is why the encryption module and the format specification are published. Finally, the approximate file size and the time you sent it remain visible: encryption protects the content, not the fact that you sent something.
- Does the recipient need to install anything?
- No. They open this page, switch to the Decrypt tab, drop the .tpenc file and type the password. No account, no install, no plugin. Because the format is publicly documented, an independent decryptor can also be written if the need arises.