What does "verification without revelation" mean, and why is it the core promise of ZKPs?

You can check that something is correct without ever seeing the underlying secret data.

* Verification without revelation: every ballot's proof is checked and the votes summed while still encrypted; only the aggregate is ever decrypted. *

This phrase captures why ZKPs are so powerful for privacy: traditionally, to verify a fact you had to see the data behind it (show your ID, hand over the document, decrypt the ballot). ZKPs break that link.

Real consequences:

• A bank can confirm you have sufficient funds without seeing your balance.
• A blockchain can confirm a transaction is valid without exposing amounts (e.g. Zcash, zk-Rollups).
• An election can be audited without de-anonymizing voters.

Tip: It flips the usual trade-off — normally more verification = less privacy. ZKPs give you both at once.