Guides

Clear, practical explainers on encryption, privacy, and sending sensitive information without leaving copies behind. No jargon for its own sake - each guide defines its terms, explains why a thing works, and is honest about the limits. Written by the team behind classified, our free zero-knowledge tool for self-destructing notes and files.

Start here - the ideas

• What "zero-knowledge" encryption actually means The provider cannot read your data - not by policy, but by design. What the term means, how it differs from ordinary encryption, and the one test that tells real from marketing. Concepts · 6 min
• End-to-end vs at-rest vs in-transit encryption Three phrases that sound alike and protect very different things. What each one defends against - and the question that cuts through the marketing. Concepts · 6 min
• Data minimization and your GDPR rights, in plain English The safest data is the data a company never collects. The minimization principle, the rights you hold over your personal data, and how to use them. Privacy · 7 min

Privacy & public policy

• Why private one-time sharing matters in the EU “Chat Control” debate Broad automated chat inspection can expose ordinary passwords and private records to classifiers, telemetry, alert queues, and review. A one-time link keeps the raw secret out of that pipeline. Policy · 9 min

How it works under the hood

• AES-256-GCM in the browser: what the Web Crypto API does The audited cryptography engine already in your browser, and how a note can be encrypted on your own device before it is ever uploaded. Technical · 6 min
• Why a secret's key belongs in the URL #fragment The part of a link after the # is never sent to any server. That quirk of web standards is what lets a share link safely carry its own decryption key. Technical · 6 min
• Password-protecting a link: PBKDF2 and key stretching explained Human passwords make weak keys. How key-stretching turns a password into a strong key while making brute-force attacks expensive. Technical · 6 min

Using it well - practical guides

• How to share a password or secret safely (and what not to do) Email and group chat leave permanent copies in places you do not control. A ranked, practical guide to sharing credentials without the fallout. How-to · 5 min
• Sending sensitive files safely: a practical checklist Attachments and drive links linger far longer than you intend. A step-by-step checklist for contracts, IDs, and keys. How-to · 6 min
• Burn-after-reading: how self-destructing messages work, and their limits How "delete on read" actually works, why one-time delivery is best-effort rather than guaranteed, and how to use it well. How-to · 6 min
• Ephemeral by design: TTL, auto-expiry, and why nothing is kept Data you never store can never leak. How time-to-live and automatic expiry shrink your exposure - and what still persists. Privacy · 6 min