Why Zcash
Privacy is normal.
Start with a boring observation: for almost all of human history, spending money told no one anything. You handed over a coin. The baker did not learn your salary. The state did not get a copy of the receipt. Your neighbor could not pull up your balance.
That was not a feature anyone designed. It was just the default property of cash. We are the first generation to seriously consider giving it up, and most people have not noticed they are doing it.
Bitcoin’s accident
Section titled “Bitcoin’s accident”Bitcoin did something genuinely new and got one thing badly wrong at the same time. The new thing: money with no issuer, no central ledger keeper, censorship-resistant. The wrong thing: it put every transaction, forever, on a public ledger anyone can read.
This was not malice. In 2009 a transparent chain was the only known way to make the consensus work without trusting a third party. But the side effect is severe. Chain analysis firms now sell the de- anonymization of that “pseudonymous” ledger as a product. Your employer paying you in BTC, an exchange KYC linking a wallet to your passport, one reused address: any of these can unravel the whole graph backward and forward in time.
A public-by-default money is not neutral. It is surveillance infrastructure that happens to also move value.
Why a promise is not enough
Section titled “Why a promise is not enough”The usual answer to “this is too public” is a policy: a privacy policy, a regulation, a company that promises to delete logs. Promises are revocable. They change with management, jurisdiction, subpoena, and breach. A privacy property you have to trust someone to keep is not a property. It is a liability with good PR.
The only durable fix is to make the private case the one the math enforces, so that no operator, miner, or government is in a position to flip it off. That is the entire bet of Zcash: a public blockchain where the consensus rules are public but the transactions are encrypted, and zero-knowledge proofs let the network verify validity without learning who paid whom or how much.
If you want the actual mechanism, the course covers it end to end: zero-knowledge proofs, notes and nullifiers, Orchard and Halo 2. This post is just the argument for why it is worth understanding.
What we are not saying
Section titled “What we are not saying”We are not saying transparency is always bad. Public goods funding, audited treasuries, and open protocol rules benefit from it. We are saying the default unit of everyday payment should be private, with selective disclosure available when you choose it, not extracted from you because the rails leak by construction.
Privacy is not the thing you justify. Surveillance is. Zcash is one of the few serious, audited, production attempts to put that principle into running code.
That is why Zcash. The next post is why we are teaching it from a peninsula in Malaysia.