Encrypt / decrypt files
Lock any file with a password, or open one you locked. Done on your device.
How to use it
- Add the files. To decrypt, add files that end in .twe.
- Type the password, twice when encrypting.
- Press the button and download the results. Keep the password safe: it cannot be recovered.
Questions
How secure is it?
It uses AES-256-GCM, key from your password by PBKDF2-HMAC-SHA-256 with 600,000 rounds. The method is standard and strong; the weak point is nearly always the password, so use a long one. Changing even one byte of an encrypted file makes it refuse to open.
What if I forget the password?
The file stays locked for good. Nothing is sent to us and no copy of the password exists anywhere.
Is the file name hidden?
Yes. The original name is stored inside the encrypted data, and the encrypted file is called name.ext.twe. Someone who has the .twe file can see its size and the .twe name, but not what is inside or what it was called.
How big a file can I use?
500 MB per file, because the whole file is processed in memory. For larger files use a desktop tool such as 7-Zip or VeraCrypt.
Can I open the file without this site?
Yes. The format is open: 4 letters TWE1, the key method, the number of rounds, a salt and a nonce (37 bytes in all), then AES-256-GCM data with the header as authenticated data. Any program that can do PBKDF2-SHA-256 and AES-GCM can read it.
Is a .twe file the same as an encrypted ZIP?
No. It is a different format, so other programs cannot open it by double-clicking. If the other person needs to open it with a common program, use Password-protect ZIP instead when it is available.
Are my files uploaded anywhere?
No. This tool runs in your browser, so your files stay on your device and are never sent to a server.
Is it free?
Yes, you can use it for free. A subscription removes limits and unlocks premium tools.