Polygon

DeFi

Ethereum

<p><a href="https://x.com/0xPolygon" rel="noopener noreferrer nofollow">@0xPolygon</a> has launched CDK Besu, a toolkit that lets banks and other financial institutions build private blockchains on Hyperledger Besu while connecting them to other networks through Agglayer, Polygon's system for linking chains. The product is live on Ethereum mainnet.</p>
<p>Besu is open-source blockchain software that Polygon says already powers platforms at DTCC, Citi and Swift. Banks choose who runs the network, and transaction data stays on bank servers rather than being published on a public chain.</p>
<h2 id="how-cdk-besu-links-private-chains-to-public-networks">How CDK Besu links private chains to public networks</h2>
<p>According to <a href="https://defiprime.com/polygon-cdk-besu-private-chain-bridge-controls" rel="noopener noreferrer nofollow">DeFi Prime</a>, Polygon added Besu as a supported Chain Development Kit (CDK) configuration on October 19, 2026. The release pairs the standard Besu client and QBFT consensus with Agglayer's bridge infrastructure, and an institution or consortium runs the validators and decides which accounts can transact.</p>
<p>Until now, connecting a private Besu-based chain to other networks required custom integrations, typically bridges that relied on groups of signers to authorise transfers, <a href="https://crypto-economy.com/polygon-launches-cdk-besu-to-connect-institutional-private-chains-to-liquidity/" rel="noopener noreferrer nofollow">Crypto Economy reported</a>. With CDK Besu, the connection to Agglayer is built in from the first block. Assets can then move between connected networks, including public ones that provide liquidity for stablecoins and tokenized assets, with transfers settled on Ethereum using zero-knowledge proofs.</p>
<p>Each transfer is checked by a proof that prevents any chain from withdrawing more than it deposited. Polygon says this limits the risk of a compromised network affecting funds deposited on other connected chains, according to <a href="https://crypto-economy.com/polygon-launches-cdk-besu-to-connect-institutional-private-chains-to-liquidity/" rel="noopener noreferrer nofollow">Crypto Economy</a>. The system verifies bridge accounting rather than every transaction executed inside each private chain, so validators keep control over what happens on their own network.</p>
<p>Institutions already running Besu can also connect existing networks to Agglayer without building a new chain from scratch, per <a href="https://www.tokenpost.com/news/technology/34926" rel="noopener noreferrer nofollow">TokenPost</a>.</p>
<h2 id="why-banks-use-besu">Why banks use Besu</h2>
<p>Besu is an enterprise-focused Ethereum client that can run on public Ethereum or as a permissioned network. The Linux Foundation's Hyperledger arm launched a Besu Financial Services Working Group in March 2024, <a href="https://www.lfdecentralizedtrust.org/announcements/2024/03/19/hyperledger-foundation-adds-citi-and-brazilian-development-bank-as-new-members-launches-financial-services-working-group" rel="noopener noreferrer nofollow">chaired by DTCC</a>, with Citi, Santander, Visa and Mastercard among its members. Citi has also described how Besu lets it use Ethereum's tooling while keeping the access controls and privacy of a private network, in a <a href="https://www.lfdecentralizedtrust.org/case-studies/citi-transforms-transaction-banking-services-with-besu" rel="noopener noreferrer nofollow">case study published by LF Decentralized Trust</a>.</p>
<p>The launch targets a long-running problem for institutions: private chains offer compliance and data control but sit apart from the liquidity on public networks. CDK Besu aims to close that gap while leaving banks in charge of validators and permissions. How many institutions adopt it remains to be seen.</p>
<h2 id="sources">Sources</h2>
<p><a href="https://defiprime.com/polygon-cdk-besu-private-chain-bridge-controls" rel="noopener noreferrer nofollow">DeFi Prime: Polygon CDK Besu, private chains and bridge controls</a><br><a href="https://crypto-economy.com/polygon-launches-cdk-besu-to-connect-institutional-private-chains-to-liquidity/" rel="noopener noreferrer nofollow">Crypto Economy: Polygon launches CDK Besu</a><br><a href="https://www.lfdecentralizedtrust.org/announcements/2024/03/19/hyperledger-foundation-adds-citi-and-brazilian-development-bank-as-new-members-launches-financial-services-working-group" rel="noopener noreferrer nofollow">LF Decentralized Trust: Besu Financial Services Working Group</a></p>

Polygon lets private bank blockchains connect to the wider crypto market

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