ZecHub
Start Here
Begin your Zcash learning journey
t) and shielded (z or u).On most blockchains there is no choice to make. Everything you send is public, forever, to anyone who looks.
Zcash gives you a choice instead. That choice is made twice: once when you pick which address to send to, and once when you decide who gets a key to read your history.
The picture below covers both.
Every Zcash payment moves between two addresses, and each can be transparent or shielded. That gives four paths, and each leaks a different amount.
The pattern is simpler than it looks: whatever touches a transparent address becomes public. A payment that stays inside the shielded pool the whole way reveals nothing but the fee.
This matters most when you withdraw from an exchange. Many exchanges only send to transparent addresses, so the withdrawal is public. Shield the funds yourself once they arrive, before you spend them.
For a deeper look at exactly what an explorer reads, see What a block explorer can see.
Privacy that you can never lift is not useful. Sometimes you need to prove something to an accountant, an auditor, or a tax office. Zcash handles this without asking you to give up control.
Spending key. Sees everything and moves funds. This is the money. It stays with you and is never shared with anyone, for any reason.
Full Viewing Key. Read-only. Shows incoming and outgoing activity and balances, but cannot spend a single zatoshi. This is what you hand to an auditor or accountant.
Incoming Viewing Key. Narrower still: it shows only payments arriving. An exchange or a merchant can run this to confirm your deposit landed, while the spending key stays on hardware that never touches the internet.
The order matters. Give the narrowest key that does the job, not the widest one you happen to have.
A viewing key cannot be revoked. There is no "undo share" button. Once someone has it, they can read that address for as long as it exists. If you need to cut access off, you move your funds to a new address.
Fees are public even in a fully shielded payment. The amount is hidden; the fee is not.
Public is permanent. Anything the chain shows today, it shows in twenty years. Deciding to shield a payment after you sent it is not a thing you can do.
If you would like to add or suggest edits to this wiki page, please head to the ZecHub GitHub repo and submit a pull request.