Cross-chain Fact
Attest an event on another chain, verified by the MPC network.
1. Read the event on its chain
Fetched from the chain's public RPC so you can check what will be verified
2. Verify with Chain Signatures and attest
How it works
The verdicts contract calls verify_foreign_transaction on the NEAR MPC signer (v1.signer-prod.testnet). Its nodes read the transaction from a quorum of RPC providers, extract the log or the instruction, and threshold-sign the result.
The contract recomputes the expected payload hash itself and checks the signature against the MPC network's public key with ecrecover. No oracle, no relayer to trust.
The nodes verify only finalized blocks: about 20 to 25 minutes after the transaction on an L2 test network, under a minute on Solana; step 1 tells you when a transaction is not final yet.
On Solana the fact is an inner instruction: the program a transaction called and the accounts and data it called it with, such as an SPL token transfer.
The attestation's subject defaults to the log's emitter or the instruction's program as a CAIP-10 id; set it to the payer or anyone else.