The blockchain trilemma can be simply understood as a problem that every blockchain faces, much like building a city. Everyone wants that city to be open to everyone, secure enough to prevent fraud, and fast and large enough to accommodate millions of users simultaneously. The problem is that over the years, it has been realized that achieving all three simultaneously is difficult, almost impossible. Prioritizing security and decentralization results in a slow system, while speed and affordability often come at the cost of decentralization.

Bitcoin is the clearest example of this trade-off. The network is highly decentralized and extremely secure, but transaction processing is slow because every node has to perform the entire verification process. Conversely, many other fast and inexpensive blockchains can process a large number of transactions, but only a few nodes control the system, reducing decentralization. Therefore, for a long time, the community believed that the blockchain trilemma was an insurmountable limitation.

When Vitalik said Ethereum “solved” the trilemma, he didn't mean that Ethereum broke fundamental rules or completely eliminated trade-offs. What Vitalik meant was that Ethereum changed the way the system is designed. Instead of requiring every node to do everything, Ethereum breaks down the work and uses mathematics to ensure that the final result remains accurate. This is a huge difference from traditional blockchain construction.

With ZKEVM, you can imagine that some nodes handle the heavy computation, then create a mathematical proof demonstrating that everything has been processed correctly. The remaining nodes don't need to repeat the entire process; they only need to verify that proof. This is similar to not needing to check every single invoice yourself, but simply trusting a mathematically audited report, where fraud is virtually impossible.