# Coldest

> Zero-knowledge cloud storage with post-quantum protection. Files and their names are encrypted on the user's device before upload; Coldest stores only ciphertext, in the EU, and cannot decrypt it.

## What it is

- End-to-end encrypted cloud storage.
- Encryption on the device: Argon2id for the password; AES-256-GCM for each file (in 1 MiB chunks), its name, and the key chain from each file up to the account's master key. Account key pairs are ML-KEM-768 (FIPS 203) with X25519, and ML-DSA-65 (FIPS 204) with Ed25519.
- The password never leaves the device. Coldest cannot reset it; users keep a recovery key.
- A web app that previews photos, video (streamed as it decrypts), audio, PDFs and text in the browser, and exports everything as a zip.
- A Mac app that puts Coldest in Finder: files download when opened, changes sync both ways, and folders can be kept downloaded for offline use.
- Sharing: links to a file or folder whose key sits after the # in the URL (never sent to the server), with an optional password and expiry.
- Version history: earlier versions of every file kept for 30 days. Deleted items stay in the trash until it's emptied.
- Stored in the EU.

## Plans

Free 2 GB; Plus 500 GB at €3 a month; Pro 2 TB at €8 a month; Max 10 TB at €32 a month. Yearly costs ten months. Prices in EUR, including VAT. Plans differ only in storage.

## Pages

- [Home](https://coldest.io/index.md): what Coldest is, features, plans, questions

## Contact

hello@coldest.io