Introduction to On-Chain Privacy

Blockchains are designed for transparency: every transfer, balance change, and smart contract call is recorded on a public ledger anyone can read. That openness supports auditability and trustless verification — but it also means financial activity is far more exposed than in traditional banking, where account details stay private by default.

Bitcoin and Ethereum use pseudonymity, not anonymity. Addresses are not tied to real names on chain, but once an address links to an identity — through an exchange KYC deposit, an NFT profile, or a public donation — the entire history attached to that address becomes analyzable.

This course surveys how privacy protocols work: privacy coins, mixers, zero-knowledge tools, stealth addresses, and compliance-oriented designs. The goal is to understand the technology and its tradeoffs — not to circumvent legal obligations.