what is troste-onion fr?

Troste Onion is a tool for sending encrypted messages, called letters, directly between two people without relying on a central server or database. Instead, each user runs a local program on their own computer that publishes itself as a Tor onion service, a type of hidden address reachable only through the Tor anonymity network. Messages travel straight between these two local programs over Tor rather than passing through any shared cloud service. The README describes this as a working prototype that has not yet gone through an independent security review. When someone sends a letter, the message is encrypted twice on their own computer, once for the recipient's key and signed by the sender, and then wrapped in a second layer of encryption tied to a shared secret code. The local program stores only the encrypted package, a hash of the secret, and an expiration date, never the secret itself or the readable text. The sender shares a special code string with the recipient, which includes the sender's onion address, an identifier, and the secret needed to unlock the outer layer. Only the recipient's own private key can open the inner, readable message. Running it requires Node.js and an internet connection to install dependencies and the Tor software bundle. Once started, it opens a local web interface where you can see when Tor has finished setting up and publishing your mailbox. The three network ports it uses are meant to stay local to your own computer and should not be exposed to the wider internet. The README is honest about its limits: the sender's computer must stay running until the letter is picked up, losing your browser's private keys makes your letters unrecoverable, and Tor reduces exposure but does not make a compromised computer safe. It is currently a desktop only tool, and the author explicitly warns it should not be deployed on services like Vercel because it needs a persistent Tor process and local storage. The README does not clearly state a software license.