Private blockchain

Definitions vary. Buterin's August 2015 account gives fully private blockchains one owner. His consortium example needs ten of 15 banks to sign blocks. Cachin and Vukolić's 2017 private-chain definition uses one single trust domain. NIST's October 2018 account recognizes an owner or consortium. The World Bank's 2017 framework separates reading from writing. Private and permissioned are therefore not synonyms. Alastria Red B calls itself public permissioned. Canton calls itself public, while transaction records stay with stakeholders.

The September 2026 ethereum.org networks page uses private to mean isolated, not protected or secure. Any full node on a private blockchain can pass its copy onward, as Besu's documentation warns. Hybrid designs lack a standards-body definition. AWS describes them as combinations of private and public elements. That vendor wording does not establish who controls each part or which records are visible. Those choices still need an explicit description for each design. A hybrid design's public component need not expose every confidential record.

Besu's QBFT uses proof of authority, but control depends on who holds keys, not just voting rules. In March 2022, five of nine Ronin validator keys were compromised, with four held by one company. Ronin then raised its validator threshold from five to eight. In October 2022, BNB Smart Chain validators halted the chain, and a client release blacklisted attacker addresses. In March 2023, Hedera operators disabled mainnet proxies after an exploit. Council node operators signed code updates, and access resumed on 11 March 2023.

TradeLens ran on Hyperledger Fabric. Maersk and IBM's November 2022 closure announcement said "the need for full global industry collaboration has not been achieved". The bank-backed we.trade wound up in June 2022 after its shareholders "pulled the plug". Marco Polo entered provisional liquidation in February 2023. B3i cited "unsuccessful funding rounds" in July 2022. Contour's November 2023 closure followed insufficient shareholder funding. ASX's Daml project paused in November 2022 over design challenges, with an A$245 to 255 million pretax charge. None involved security breaches.

In November 2026, Kinexys, multi-bank Partior and HSBC's deposit service are live. JPMD, J.P. Morgan's deposit token, launched on Base in November 2025, with Canton expansion phased through 2026. Broadridge DLR processed $7.5 trillion in September 2026 on Canton. DTCC's Tokenization Service launched on 28 October 2026 across Canton and its private Besu network. Swift announced a shared-ledger prototype in September 2025. Project Agorá tested real value in July 2026, but remains a prototype. These are different stages, not equivalent adoption claims.

Azure Blockchain Service retired in September 2021. IBM Blockchain Platform support ended in April 2023. IBM directed customers to its Hyperledger Fabric support. Amazon Managed Blockchain stopped accepting new customers on 29 October 2026, with access ending in September 2027. AWS lists "an AWS database" among Fabric migration routes. Its guidance says network state and identities are rebuilt, not copied. Oracle Blockchain Platform and Kaleido remain offered in November 2026. A managed private blockchain therefore needs an exit plan, not just an initial hosting quote.

At the November 2026 readings, private charges are fixed per member, while public fees scale with transfers. Neither column prices the people who maintain the process. Staff, governance and legal work sit outside infrastructure quotes, alongside audits. The write-offs and failed funding rounds above show why a hosting price cannot stand in for total exposure. No source reviewed supplies a like-for-like comparison for the same workload. A private blockchain cost assessment must keep those gaps visible. Public gas prices also change after each quoted reading.