Hemmelig

It provides a web‑based interface for creating encrypted messages that are stored only as ciphertext. Encryption is performed in the browser using AES‑256‑GCM, so the server never sees the plaintext or the encryption keys. Users can set an expiration time, a limit on the number of views, and an optional password; additional controls include IP‑based access restrictions, file attachments, rich‑text formatting, QR‑code links, and multilingual support. Webhooks can notify external systems when a secret is accessed or destroyed.

The tool is intended for developers, security‑conscious teams, and private individuals who need to transmit sensitive data across organizational boundaries or within personal communications. It can be run as a self‑hosted service via Docker, Docker Compose, or Helm, and a command‑line client enables automation and CI/CD integration. The project is open‑source under the MIT license, offers a free tier without subscription, and is marketed as stable and self‑hostable.