A mechanism for supplying information a contract cannot directly observe.
LET’S PICTURE IT
A classroom judge can record a sports result supplied by a reporter. The rule for trusting the reporter is part of the system.
SEE IT FOR YOURSELF
Receive, check and share across independent nodesStep 1 / 4
A node receives a proposed transaction or block-related message. Receipt is not the same as accepting its claims.
A node receives a proposed transaction or block-related message. Receipt is not the same as accepting its claims.The node checks the relevant authorization and protocol rules. Popularity does not make an invalid state transition valid.Valid candidate data can propagate to peers. Connections and timing differ, so there is no perfect simultaneous worldwide view.Peers validate under the same protocol rules. This illustration is about verification and propagation, not a complete proof-of-stake consensus algorithm.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
The outside-world gap
A contract can calculate from its inputs and chain context. It cannot automatically know an offchain event, market quote or physical delivery status. An oracle design brings relevant information into a form the contract can use.
Different designs make different assumptions
One design may trust a specific signer; another may aggregate several reports or use proofs and additional mechanisms. A label such as oracle does not specify freshness, availability or resistance to manipulation by itself.
Correct code can still use a bad input
A lending calculation can follow its arithmetic perfectly while using a stale or manipulated price. Applications need rules for checking the conditions under which a supplied input is acceptable.
Separate the question being verified
A contract might verify who signed a report without proving the report matches reality. Read signatures and contract limits to distinguish authorization, computation and truth about external events.
QUICK CHECK · NO PRESSURE
Does verifying a report’s signature alone prove the report is factually true?
A signature establishes authorization under verification rules, not the truth of the external observation.