Time-Locked Message

Seal a message that nobody can open until the date and time you choose.

Processed locally — nothing is uploaded

Your message0 / 20,000 characters

Opens

How the lock works, and its limits

Sealing happens on this device and sends nothing anywhere. The message is encrypted to a future round of drand, a public randomness network run by independent organisations that publishes a signed value every three seconds. The signature for your round does not exist yet, and it is the only key that opens the message.

Opening fetches that one public signature from a drand relay, checks it against the network's public key, and decrypts in the browser. The message itself never leaves the device, in either direction.

Limits. Anyone holding the link can read the message once the time passes: this is “sealed until”, not “for your eyes only”. If the drand network stopped for good, sealed messages could not be opened. And sealing does not prove when you sealed: to show a prediction came first, post the link somewhere that records the date.

Network: drand quicknet · scheme bls-unchained-g1-rfc9380 · chain 52db9ba70e0cc0f6… · format: age with a tlock stanza, compatible with drand's tle tool and Timevault.

About Time-Locked Message

There is no password to share or forget: the key is a signature the drand network publishes at the chosen moment and cannot publish sooner, so the person who wrote the message is locked out exactly as firmly as everyone else.

Write a message, choose when it opens, and seal it. What comes back is a link and a block of sealed text. Either one can be posted, forwarded or stored anywhere, and until the moment you chose it reveals nothing to anyone. When that moment arrives, opening the link shows the message to whoever holds it: the person you sent it to, you, or anyone they passed it on to. Before then, nobody can read it, and that includes the person who wrote it.

The lock is timelock encryption built on drand, a public randomness beacon run by a group of independent organisations known as the League of Entropy, among them Cloudflare and Protocol Labs. Every three seconds the network publishes a numbered round carrying a signature that its members produce jointly, so no single operator can produce one early. A message is encrypted to one future round using identity-based encryption on the BLS12-381 curve, which makes the decryption key exactly that round's signature. Until the network reaches the round, the key does not exist anywhere.

Sealing sends nothing anywhere. The network's public key is built into this page, so the message is encrypted on your device without contacting drand or this site, and nobody learns that a message was written. Opening asks a drand relay for one public signature, verifies it against that same key, and decrypts in the browser. A relay can decline to answer, but it cannot forge a signature that passes the check. The sealed message travels in the part of the link after the # sign, which browsers never send to a server.

Three limits are worth knowing before relying on it. The lock is about time, not audience: once the moment passes, anyone holding the link reads the message, so it is the wrong tool for a secret meant for one person. Opening depends on drand still publishing at the chosen time, which it has done since 2019, a strong record rather than a guarantee for a message sealed a decade ahead. And a sealed message shows when it opens, not when it was written, so a prediction only proves itself if the link was posted somewhere dated before the event.

The sealed text is a standard format: an age file with a tlock stanza, the same thing drand's own command-line tool, tle, and its Timevault page produce. A message sealed here opens with those tools, and one sealed with them opens here. Nothing about opening it depends on this site still existing, only on the network and the format, both of which are public.

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Frequently asked questions

Can I open my own message early?

No, and neither can anyone else. The key is a signature that will be published at the round you chose; until then it has not been created, so there is nothing to find, guess or request. Writing the message does not give you a copy of the key either. The flip side is worth taking seriously: a message sealed for next year cannot be recovered sooner if you change your mind.

Does anyone see what I wrote?

No one sees the words. Sealing happens entirely in your browser and makes no network request at all. Opening makes one request, to a drand relay, for the signature of a single round, which tells the relay that someone wanted that round and nothing about the message. The link keeps the sealed message after the # sign, the part a browser does not send when it loads a page.

How exact is the unlock time?

Within three seconds. drand publishes a round every three seconds, so a message is sealed to the first round at or after the time you pick: it can open up to three seconds late, never early. The page shows the time in your own time zone, and the recipient sees the same moment in theirs.

What happens if the drand network stops?

A message whose round never arrives stays sealed, with no fallback, because a fallback would be a way to open it early. drand has run continuously since 2019 with operators in several countries, which makes a message for next month or next year a safe bet. For something sealed decades ahead, keep in mind that no network can promise that.

Can this prove a prediction?

Yes, with one extra step: post the link somewhere that shows a date, such as a group chat, a social post or an email, before the event. The seal proves nobody could read your prediction beforehand, and the dated post proves it existed beforehand. Together they show you called it without letting anyone see the call in advance.

How long can the message be?

Up to 20,000 characters. A link can carry about 1,300 characters of plain English; a longer message still seals, and comes with the sealed text to copy or download instead, which opens exactly the same way.

Pro Tips

→Try the one-minute preset with a throwaway message first, to watch the whole cycle of sealing, counting down and opening before you seal something that matters.
→Keep the sealed text as well as the link. Some chat apps cut long links short, and the text block opens identically wherever it is pasted.
→For a prediction or a sealed bid, share the link publicly before the deadline. The date on that post is what proves when you committed.
→Tell the recipient when it opens in the message that carries the link, so they come back at the right time instead of meeting a countdown.
→Do not seal anything that must stay private after the unlock time. If only one person should ever read it, encrypt it with a password as well.

Common Use Cases

•Predictions about a match, an election or a launch, revealed only after the result is known.
•Sealed bids or votes collected in a group chat, where nobody may see another number before the deadline.
•A note for a birthday, a graduation or an anniversary, written today and readable on the day.
•Quiz answers, puzzle solutions and spoilers shared with the question but locked until the reveal.
•A message to your future self: goals written in January and opened in December.

How It Compares

Services that email a letter to your future self, such as FutureMe, keep the message on their servers until the date, so the lock is their promise not to read it or lose it. drand's Timevault page and tle command-line tool do real timelock encryption and are the reference implementations, written for developers. This page uses the same format, keeps the words on your device, and turns the result into a link with a countdown that anyone can open without knowing what a beacon is.