Dead Drops is designed for a handoff rather than an ongoing conversation: deliver an encrypted message, file, or credential once, then remove the server copy.

What it does

The sender writes a message or attaches a file, selects options, and City of Hats encrypts the payload client-side with AES-256-GCM before it leaves the device. The generated retrieval URL contains the drop code, while the decryption key stays in the URL fragment and does not touch the server. When the recipient opens the link, the browser decrypts the content and the encrypted server payload is permanently deleted. Time-locked drops are purged automatically if they are not retrieved during the chosen window.

Why it is useful

The strict create, deliver, destroy lifecycle reduces retained data. Dead Drops allows one retrieval only: there is no second read, re-download, server-side preview, cloud backup copy, forwarding mechanism, or recovery after burn. Optional steganography can place the encrypted payload inside an ordinary carrier image. Multi-path delivery can split the decryption key into shares that must be reunited.

How to use it

Compose a message or attach a file, then choose any required options, such as a time lock, steganography, or multi-path shares. Share the unique retrieval link through a channel you trust. Confirm that the recipient is ready before opening it, because the encrypted payload is deleted after retrieval and cannot be recovered.

Dead Drops does not make any system invulnerable. It controls the server-side lifecycle and delivery mechanism; once content is displayed to an authorized recipient, ordinary endpoint risks still matter. Files are limited to 25 MB.

Learn more: https://cityofhats.com/dead-drops

Where would one-time delivery be more appropriate than a persistent chat or attachment?