THE ROMANCE OF CRYPTOGRAPHY
More than a countdown.
A future signature is part of what is needed to decrypt the file.
We do not store your files or send reminders.
Your encrypted file, opened with a verified future signature.
Problem, design and limits
drand and tlock make a future round's signature a condition for decryption. Pathadd does not store the file or release a key on a schedule.
Problem: why can an encrypted file be delivered now but opened only later?
A countdown or hidden button can be changed and cannot enforce a cryptographic time condition. Asking a website to release a passphrase later requires long-term trust that it stays online and does not release it early.
Here, a future public signature is needed to recover the data key. The encrypted file can be created today without that signature. The sender still has the original file and can disclose it separately; the time lock cannot prevent that.
Design: drand threshold signatures, tlock key encryption and local chunk decryption
Independent nodes each hold a secret share and jointly produce a public beacon using threshold BLS signatures. One node cannot do it alone. This tool uses drand Quicknet, with a round roughly every 3 seconds. The browser verifies signatures against the pinned mainnet public key rather than trusting an API response alone.
tlock uses identity-based encryption to bind access to a future round. A random data key encrypts the file, and tlock encrypts that key. Recovery requires the valid signature for that round. It is the future signature that is not yet public, not every key in the process.
The date maps to the first drand round at or after local midnight. The exact time and round are stored in the file. Changing its name, a countdown or the local clock cannot produce a valid signature. Encryption uses public parameters; decryption requests only public beacons. Files, original names and data keys are not sent to drand.
Files up to 1 GiB use a separate .enc format. Select the encrypted file and an output folder, then keep the page open and online while it waits for a valid signature and saves the plaintext. Existing files are not overwritten. This format is not compatible with Personal Vault, secure delivery or Time Seal.
Limits: a start time, not an expiry date or recipient authentication
Security relies on cryptographic assumptions and drand threshold cooperation, not blockchain-style consensus. Enough colluding nodes or leaked secret shares could produce a signature early. If signing stops or beacons become unavailable, decryption may be delayed or impossible.
The tool does not run in the background after the page closes. Select the encrypted file again to resume. Anyone with the file can decrypt it once the valid signature is public. There is no passphrase, recipient restriction, revocation or recovery. The chosen date does not impose claim limits or an authorization deadline.
Back up the .enc file, for example by emailing it to yourself; a copy of the original plaintext is not a time-locked backup. This site does not send email or store files. Email storage is not guaranteed forever, so keep an independent copy. Long-term access still needs an intact encrypted file, compatible tools and a valid beacon.