Share Secrets Securely with Cryptgeon

Ever needed to send a password, API key, or a sensitive document to someone but felt uneasy about it sitting in a Slack channel or email thread? We've all been there. Most options are either inconvenient, not truly secure, or require trusting a third-party service. Cryptgeon offers a refreshingly simple and secure alternative for sharing sensitive snippets and files.

Cryptgeon is an open source, secure note and file sharing service. Think of it as a more private, self-hosted alternative to services like Pastebin, but with a core focus on security and ephemerality. The data is encrypted on the client-side before it ever reaches the server, meaning the server never has access to the unencrypted content.

What It Does

In practice, you go to a Cryptgeon instance, paste your text or upload a file, and set a view and expiration limit. Cryptgeon then generates a link. You share this link (and the separate password key, if you set one) with your intended recipient. Once they view it or the expiration time hits, the note or file is automatically destroyed from the server.

Why It's Cool

The clever part is in the implementation. Cryptgeon is built with Rust on the backend and Svelte on the frontend, a combo known for performance and a great developer experience. The real magic, however, is the client-side encryption using the AES-GCM algorithm. This means the secret is encrypted in your browser using a key derived from the URL fragment. The server only ever handles the encrypted data and has zero knowledge of the actual content. It's a true zero-trust model for secret sharing.

This approach solves the trust problem. You don't have to trust the server or its administrators because they physically cannot read your data. It's all handled by the client. Plus, being open source means the code can be audited by anyone, adding a layer of transparency you just don't get with proprietary services.

How to Try It

The easiest way to see Cryptgeon in action is to check out the public demo. Head over to cryptgeon.org and try creating a note. No installation needed.

If you're convinced and want to run your own instance for your team or personal use, it's straightforward thanks to Docker. The project provides a simple docker-compose.yml file to get you up and running in minutes. Just clone the repo and run:

git clone https://github.com/cupcakearmy/cryptgeon
cd cryptgeon
docker-compose up

You can find more detailed deployment instructions and configuration options in the project's GitHub repository.

Final Thoughts

Cryptgeon nails a specific use case perfectly. It's not trying to be the next big communication platform. It's a sharp, focused tool for developers and privacy-conscious users to share secrets safely. The client-side encryption model is the right way to build this kind of service, and the fact that it's open source and self-hostable makes it a no-brainer for many use cases. Next time you need to share a config file or a credential with a coworker, this might just become your go-to tool.

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