Prividium is best understood as a Bank Stack: private where it matters, connected where it counts. Imagine a custodian bank responsible for safeguarding assets on behalf of asset managers, pension funds, and insurers. Internally, it runs complex workflows for asset issuance, collateral management, and end-of-day reconciliation. These processes demand confidentiality, strict access control, and regulatory oversight. At the same time, clients increasingly expect assets to be programmable and interoperable with on-chain markets. Public blockchains offer global settlement and composability, but they expose positions, counterparties, and operational logic — a non-starter for custodial infrastructure. Prividium on @zksync is designed for this boundary. The bank deploys a private, permissioned ZKsync Chain within its controlled infrastructure. Asset movements, collateral adjustments, and internal reconciliations execute privately. The full system state remains confidential, and only authorized participants can interact with specific workflows. Rather than publishing activity publicly, the system anchors zero-knowledge proofs and state commitments to Ethereum. Ethereum becomes the verification layer, allowing external parties to independently confirm that rules were followed without seeing balances, client identities, or internal processes. Compliance is enforced at the infrastructure layer. Role-based permissions define who can issue assets, move collateral, approve settlements, or review activity. Regulatory requirements are embedded directly into execution, reducing reliance on after-the-fact reporting. When oversight is required, selective disclosure allows regulators or auditors to verify specific events, such as asset backing, custody integrity, or settlement finality, without exposing unrelated client data or proprietary workflows. Crucially, the private system is not isolated. Through native interoperability, assets issued and managed privately can interact with Ethereum and the broader ZKsync ecosystem when needed, without third-party bridges or custodians. This enables controlled access to public liquidity, standardized settlement, and ecosystem composability. The result is a shift in how institutions use blockchain. Execution stays private. Verification becomes public. Connectivity remains optional and governed. With Prividium on @zksync, blockchain becomes internal financial infrastructure, defined by privacy, compliance, and cryptographic assurance, not public exposure.