Flare launches confidential compute on Songbird as Hex Trust’s USDX becomes first stablecoin with private proof of reserves

Flare, the blockchain for data, has brought Flare Confidential Compute (FCC) to Songbird, its canary network. FCC processes private institutional data and returns signed results that smart contracts can verify onchain, without the data itself becoming public. 

The first institutional application is a Proof of Reserves extension, with Hex Trust’s USDX becoming the first stablecoin to use the technology.

Verifying private data without making it public

Smart contracts can only act on data they can verify. While public information is supported on Flare through the Flare Time Series Oracle (FTSO) and the Flare Data Connector (FDC), institutional data such as reserve balances, fund NAVs, collateral positions, credit information and compliance records often needs to remain private.

FCC processes private inputs inside a registered Trusted Execution Environment (TEE) and returns a signed result that contracts can verify before relying on it. The underlying data remains private, with only the resulting aggregate conclusion published onchain.

Hex Trust’s USDX becomes first stablecoin on FCC Proof of Reserves

The first FCC application is a Proof of Reserves extension designed for assets whose backing includes both public and private components. Hex Trust is using the extension for USDX, its 1:1 USD-referencing stablecoin.

Hex Trust provides USDX reserve data from two sources, including a public reserves amount and a restricted cash reserves amount. The extension reads the data inside the TEE, checks the combined total against USDX supply across the ecosystem, and signs a result showing whether USDX is backed 1:1 or better. Only the result is published, without exposing the underlying reserve balances.

USDX is a collateral asset in the FAssets system on Songbird, and its feed is migrating to this reserve-based reference. The same result provides decentralized exchanges with a basis for pricing USDX, while feed metadata indicates whether reserves meet the required coverage threshold at each update.

“Integrating Flare Confidential Compute enhances the trust layer for institutional adoption by enabling real-time, onchain verifiability of USDX reserves and thus manifesting its position as a trusted stablecoin in the Flare ecosystem” said Ben Usinger, Head of Stablecoins at Hex Trust.

How FCC verifies results: Provider signatures, approved code and hardware attestation

FCC is designed so that a contract can verify not only the result, but also the conditions under which that result was produced.

Songbird data providers relay and sign each instruction under Flare’s signing policy. The TEE executes an instruction only after it carries a weighted majority of provider signatures. The provider set is the same one that operates the FTSO and FDC.

Each supported FCC code version is represented by the hash of a reproducible container image that has been approved onchain. A machine running unapproved code cannot register with the network, while new versions must pass the same approval process before they can be used. This makes code upgrades an onchain event.

A TEE joins an extension by presenting a hardware attestation showing that it is running an approved code version. The attestation is verified through the FDC and recorded onchain. The machine’s signing key is generated inside the enclave at boot and does not leave it.

The TEE then signs the resulting output using its registered identity. A verifier contract, the TEE registry, checks that signature before the result can be stored or used by other contracts.

For Proof of Reserves, FCC combines public reserve components, private reserve records and token supply in a single calculation. The extension applies a defined coverage rule, which can range from a single threshold to a multi-condition policy. The resulting conclusion is published without exposing the private figures that contributed to it.

One framework for public and private data

FCC extends Flare’s data infrastructure to information that cannot be published directly onchain. The FTSO provides public market data, while the FDC verifies information from other blockchains and Web2 systems. FCC adds confidential data and computation under the same network-level provider set and signing policy.

This creates a common framework for applications that need verified results from private information. Beyond Proof of Reserves, potential applications include lending markets that combine public asset prices with private coverage information, tokenized funds that calculate verifiable NAVs from undisclosed holdings, and credit or compliance applications that require a verifiable conclusion without exposing underlying records.

Live on Songbird first, with Flare deployment to follow

FCC is initially live on Songbird, Flare’s canary network, following the acceptance of STP.13 in July 2026. A deployment on Flare will follow separately.

The initial Songbird deployment is supported by TEE machines running on Google Cloud confidential computing and operated by the Flare Foundation. The architecture is designed to support a broader distribution of operators and hardware vendors over time.

The FCC extension framework will open to builders later in the bootstrap period. Developer documentation covering the architecture, extension development, registration and onchain verification is available through the Flare Dev Hub.

To learn more about Flare Confidential Compute and begin building, visit the Flare Dev Hub: https://dev.flare.network/fcc/overview.