[From September 17. When released this should make zk-snark based privacy much more practical.]
"Today, zcash, the seventeenth-largest cryptocurrency by market capitalization, uses the bleeding-edge cryptographic technique zk-SNARKs to hide balances and user addresses, but the technique comes with a drawback that's hard to ignore: anonymous transactions are sluggish.
While normal transactions take seconds to create, shielded transactions using zk-SNARKs take one to two minutes. That's why engineers have been exploring ways to cut down the time needed to securely generate shielded transactions."
https://www.coindesk.com/better-faster-zk-snarks-zcash-developers-release-new-privacy-tech/
"Today, zcash, the seventeenth-largest cryptocurrency by market capitalization, uses the bleeding-edge cryptographic technique zk-SNARKs to hide balances and user addresses, but the technique comes with a drawback that's hard to ignore: anonymous transactions are sluggish.
While normal transactions take seconds to create, shielded transactions using zk-SNARKs take one to two minutes. That's why engineers have been exploring ways to cut down the time needed to securely generate shielded transactions."
https://www.coindesk.com/better-faster-zk-snarks-zcash-developers-release-new-privacy-tech/