# ZK Layer — zero-knowledge proof technologies in simple terms
ZK (Zero-Knowledge) is one of the most powerful and beautiful technologies in the crypto world. It allows you to prove that data is correct without revealing the data itself. It sounds like magic, but it already works in real networks.
In the context of blockchains, ZK technologies are used to create ZK-rollups — solutions that bundle transactions, process them off L1, and send only the mathematical proof of correctness to the network. Ethereum verifies the proof without executing each operation — and this saves huge resources.