All tools › One-time codes
Authenticator code
The address an authenticator scans, drawn as a code on this device.
It runs entirely in this browser tab: the passwords, keys and messages you type are never uploaded, and the tool makes no network request while it works. Open your browser's network panel and try it — nothing leaves the page.
Settings
- Who it is for
- The name an authenticator shows beside the code.
- The secret
- In Base32, if you already have one. Leave it empty and a fresh one is made here.
- How long a secret
- A number from 10 to 64.
- Use the secret I gave
- For rebuilding a code you already set up, rather than starting again.
- How many digits
- A number from 6 to 8.
- Step length
- A number from 10 to 300.
- Digest
- Choices: SHA-1, SHA-256, SHA-512.
- Written as
- A picture to scan, blocks to paste into a terminal, or the address itself. Choices: As a picture, As blocks of text, As the address.
How to use it
- Paste your text into the box above, or open a file.
- Adjust the settings beside it until the result is what you wanted.
- Copy the result, or save it as a file. The result updates as you type.
Questions
- Is this audited cryptography?
- No, and every result that rests on a cipher says so. Each algorithm here matches the vectors its own standard publishes, which proves it computes the right function; it does not prove there is no timing leak, and no test in this workspace could. For anything that matters, use an implementation somebody has reviewed.
- Is what I type uploaded anywhere?
- No. The whole tool is carried as WebAssembly and runs on your own device. No password, key, message or certificate is sent anywhere, and nothing is stored beyond the settings you chose.
- Why does a tool ask me for a word list?
- Because shipping one would be worse than not. A usable list of common passwords is bigger than everything else on this page put together, and a small one is actively harmful — it calls a leaked password uncommon. Paste your own and it is used, and it does not leave the page either.
- Does a check here mean my key is safe?
- It means the shape matched or the arithmetic came out. A scanner finds what it was written to find; a certificate that parses is well formed, not trusted; a password that is not in your list is a password nobody has leaked yet. Each tool says which of those it just told you.
Other tools for one-time codes
TOTP code
The code a secret gives at a time you name, and the steps either side.
Backup codes
Codes for the drawer, with the hashes a server should keep instead.
All eighteen tools