Module 01

What is Midnight, and why does it exist?

Most public blockchains have one privacy setting: none. Every balance, every contract call, every piece of state is visible to anyone who looks. That rules out huge categories of real activity — payroll, medical records, identity, B2B contracts — anywhere a fact needs to be verified without being published to the world forever.

Midnight's bet: privacy doesn't have to be all-or-nothing. Its core idea is programmable privacy — a developer decides, field by field, what's public and what's shielded, using zero-knowledge proofs so the network can still verify a claim is true without seeing the data behind it.

Three ideas that matter most

• Selective disclosure. An app can reveal exactly the fact needed — e.g. "this user is over 18" — without revealing the birthdate that proves it.
• Zero-knowledge proofs, made ordinary. Midnight's contract language, Compact, is designed so a web developer can write privacy-preserving logic without personally understanding the underlying proof math.
• Dual-component architecture. Shielded (private) and unshielded (public) state are separated at the protocol level, not bolted on afterward.

Check your understanding

1. What does "selective disclosure" mean, in a sentence?
2. Why does Compact exist — what does it remove for a web developer?
3. Name one real use case awkward on a fully public chain, and awkward on a fully private one.