Beyond voting, what are some real applications of zero-knowledge proofs?

Privacy-preserving authentication, anonymous credentials, confidential blockchain transactions, and scalable "rollup" proofs.

ZKPs have moved from theory to production, especially in cryptocurrency and identity:

• Authentication: prove you know a password/key without transmitting it.
• Anonymous credentials / age checks: prove "I'm over 18" or "I'm a citizen" without revealing your identity or birth date.
• Secure online petitions: provably sign or support a petition without exposing who you are.
• Confidential transactions: Zcash hides sender, receiver, and amount while still proving no money was forged.
• zk-Rollups (zk-SNARKs/zk-STARKs): compress thousands of transactions into one small proof to scale blockchains.
• Compliance: prove a dataset meets a rule without disclosing the data.

Go deeper:

• Anders Brownworth — Zero-Knowledge Proof demo — an interactive walkthrough of a ZKP protocol you can click through yourself.