Once, when asking a compliance officer why they don't put assets on the chain, he responded, "Can our competitors see our balance sheet in real time?"

The answer is harsh: on a fully public chain, yes, they can see it. But if you switch to a private chain, liquidity drops to zero, effectively isolating yourself on a financial island.
The emergence of @zksync Prividium is changing this dilemma. It is not another alternative to L1 but a key layer in the "Ethereum banking stack."
The technical architecture is actually simple: Prividium is a permissioned chain based on ZK Stack, operating in Validium mode.
All transaction executions are completed within an environment controlled by the institution, which can be its own data center or a secure cloud environment.
Sensitive data remains off-chain, with no transaction details exposed externally. Only encrypted commitments and zero-knowledge proofs are published to @Ethereum, with the mainnet handling verification and finality.
But the real key is not privacy itself, but how it connects to Ethereum.
Through ZKsync's L1 interoperability solution, users on the Prividium chain can natively access Aave, borrow GHO, and settle assets directly on L1—no bridges, no custody, no network switching. Operations within the private environment can seamlessly invoke liquidity from the public markets.
This is very different from traditional private chains: private chains are closed systems, and liquidity begins to dry up the moment they connect.
It also differs completely from the logic of alternative L1s: replacing L1 with a different settlement layer. Prividium makes Ethereum the only settlement layer, while execution happens in a private environment.
Recently, Vitalik has repeatedly emphasized that L2 should not just replicate the general execution environment of L1 but should introduce native capabilities that L1 cannot provide.
Prividium is a concrete embodiment of this direction. It is not meant to be a "faster Ethereum," but to enable regulated capital to use Ethereum.
This architecture is already running real use cases. Banks, through Memento, have built Prividium chains under the framework of the Financial Supervisory Authority's Project Guardian for on-chain fund management—this is the first key for institutional capital to tentatively enter.
The "Ethereum banking stack" is not just a marketing concept but a structural choice: privacy execution + Ethereum settlement + native interoperability.
It allows institutions to gain privacy without isolation, achieve compliance without fragmentation, and access Web3 without sacrificing liquidity.
When institutions can finally work behind closed doors without leaving Ethereum’s big network, the so-called "banking stack" truly becomes meaningful.