Which Blockchains Are Going Private?

The list keeps growing. Sui, zkSync, Polygon, and Solana were all built as fully transparent public networks, and all four are now adding confidential transactions. Cardano's new Midnight sidechain is doing the same for that ecosystem. The goal is not anonymity. It is privacy that banks, auditors and regulators can sign off on.

Why the sudden rush to hide transactions? Public blockchains were built on transparency; anyone can read every balance and every transfer. That was a selling point for years. It is now a barrier to the institutions that crypto spent 2025 courting.

A bank will not run payroll, treasury moves, or client settlement on a ledger where competitors can watch in real time. Tokenized real-world assets, encrypted stablecoin flows, and compliant DeFi all need a way to keep amounts and counterparties private while still proving the math is correct.

The common thread is confidentiality, not anonymity. The details of a transaction stay hidden from the public while the network can still verify them, and most of these chains let users reveal specific data to an auditor or regulator when required. It is privacy built for regulated finance, not for dodging it.

The public chains going confidential Four networks are driving the trend, each with a different approach and a different stage of progress.

Sui Co-founder Adeniyi Abiodun confirmed on June 5 that Sui (@SuiNetwork) Confidential Transfers are coming this year. The feature uses range proofs to hide transfer amounts while still enforcing supply, so unauthorized minting stays impossible by design, per Abiodun. It sits inside a broader 2026 roadmap that already includes gasless stablecoin transfers, on a network that has processed more than $1 trillion in stablecoin volume since August 2025. No firm launch date has been given.

zkSync Matter Labs has built its institutional play around Prividium, private permissioned chains that run as validiums. Execution and data stay off-chain in infrastructure that the institution controls, and only a zero-knowledge proof settles to Ethereum. The first production deployment, Memento ZK Chain, was built with Deutsche Bank. A separate effort, the Cari Network, is onboarding five US regional banks with more than $600 billion in combined deposits, with a pilot targeted for the third quarter of 2026.

Polygon In May, Polygon (@0xPolygon) added a privacy configuration to its Chain Development Kit, letting institutions launch private chains that still tap public liquidity through AggLayer. Built with Succinct Labs, the setup keeps raw transaction data inside institution-owned infrastructure and sends only a cryptographic commitment and a proof to Ethereum. The principle Polygon repeats is private data, public verification. It fits the company's Open Money Stack framing as it winds down its zkEVM mainnet beta.

Solana @solana got here first, but with an asterisk. Its Confidential Transfers shipped inside the Token-2022 standard, using homomorphic encryption and zero-knowledge proofs to hide transfer amounts and balances, with an optional auditor key for compliance. The catch is that the ZK ElGamal proof program the feature relies on has been switched off on mainnet since mid-2025, after a researcher discovered a flaw that could have enabled the forging of valid proofs. It stays disabled pending a security audit, so confidential transfers are not usable on the live network for now.

Where does Midnight fit? Midnight is not a public chain bolting on privacy. It is a new privacy-first sidechain that extends Cardano. It launched a federated mainnet on March 31, 2026, with Google and Vodafone among the node operators. It uses a dual-token model, NIGHT for governance and DUST for transaction costs, plus a dedicated language for confidential smart contracts. Founder Charles Hoskinson (@IOHK_Charles) calls the approach "rational privacy" and has made it clear that Midnight is not chasing Monero's users. Selective disclosure is built in, aimed