Attestation Types

FDC Attestations provide cryptographic proofs for data originating outside Flare's EVM state. They enable smart contracts to verify external data trustlessly. For example, FDC attestations can validate:

• Non-Payment Verification: Confirm whether a payment has not been made on a UTXO chains like Bitcoin or Dogecoin.
• Event Log Authentication: Verify event logs generated by transactions on EVM-compatible blockchains.

FDC currently supports the following six attestation types:

AddressValidity

Validates if a string is a legitimate external blockchain address.

JsonApi

Data retrieval from Web2 JSON APIs with JQ transformations.

BalanceDecreasingTransaction

Detects a transaction decreasing the balance of an address.

ConfirmedBlockHeightExists

Assertion whether a specified block number is confirmed.

EVMTransaction

Information about an EVM transaction including events.

Payment

Information about native token payments on an external chain.

ReferencedPaymentNonexistence

Payment due by the agreed deadline has not been made.