This is a decent explanation of how ZCash improves privacy over Bitcoin: https://z.cash/technology/zksnarks/
TL;DR: a blockchain is a public ledger, and thus all transactions are visible with amounts, source and destination. zk-SNARK is a method for encrypting transactions, but in a way that all nodes can still verify that the transaction is valid (not spending more money than you have, not double-spendoing the same money, etc).
tiflolinux.org - GNU Social is a social network, courtesy of tiflolinux.org. It runs on GNU social, version 2.0.1-beta0, available under the GNU Affero General Public License.
All tiflolinux.org - GNU Social content and data are available under the Creative Commons Attribution 3.0 license.