WispFile

How to password-protect a shared file

By the WispFile team · Updated 24 September 2026

A password on a file link means someone who gets hold of the link still cannot open the files without the password, which you send another way. On WispFile the password is checked in the receiver’s browser and never reaches our servers; it unlocks the key that decrypts the files.

Key facts

  • Send the password by a different channel from the link: a call, a text, a chat.
  • WispFile passwords are free on every plan.
  • The password never leaves the browser; a wrong one fails there.
  • Pair it with a one-download link for the most sensitive files.

How to add a password

  1. Add your files on WispFile.
  2. Turn on Password and type one. Longer beats cleverer.
  3. Share the link one way and the password another.

How it protects the files

Every WispFile link carries a 256-bit key after the #, which browsers never send to a server. With a password, that key is itself locked: it is wrapped with a key derived from your password (600,000 rounds of PBKDF2), so the link alone cannot decrypt anything. The receiver types the password, their browser unwraps the key, and only then can the files be read.

Because the check happens in the browser, a wrong password is caught there, and there is no password database on our side to leak.

When a password is worth it

  • The link goes through a channel others can read, such as a shared inbox or group chat.
  • The files are confidential: contracts, IDs, medical or financial records.
  • The recipient might forward the email without thinking.

Frequently asked questions

Can WispFile recover a forgotten password?

No. We never see it, so nobody can recover it. Create a new link with a new password.

Is a password link end-to-end encrypted?

Yes. Every link is; the password adds a lock on the key.

Does the receiver need an account?

No: the link and the password are all they need.

Related guides

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