All tools › One-time codes
TOTP code
The code a secret gives at a time you name, and the steps either side.
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
- The moment
- In seconds since 1970. There is no clock here — the framework has a date and not a second — so a code for a time it guessed would simply be wrong. A number from 0 to 9223372036854775807.
- How many digits
- Four digits is ten thousand possibilities, which a phone allows three tries at. A number from 6 to 8.
- Step length
- Thirty seconds is what every authenticator assumes and almost no server changes. A number from 10 to 300.
- Digest
- SHA-1 is what every authenticator does, whatever the standard allows; the other two are correct and will not scan. Choices: SHA-1, SHA-256, SHA-512.
- Steps either side
- A server usually accepts one step either side, to allow for clocks that disagree. A number from 0 to 10.
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
Authenticator code
The address an authenticator scans, drawn as a code on this device.
Backup codes
Codes for the drawer, with the hashes a server should keep instead.
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