Tokens, events and approvals
Why a token transfer is a log entry, what an approval allows, and how fake tokens exploit familiar names.
A token is a contract that keeps its own list of who holds how much. Moving a token means asking that contract to change its list. The contract then writes a Transfer event to the transaction log. Explorers and tools read those events.
An event is what the contract reported. A well-behaved token reports accurately. A malicious one can emit events that look like transfers from well-known addresses without moving anything of value.
#Approvals
An approval gives another address permission to move your tokens later, up to a limit, without a new signature from you. For an NFT collection, one approval can cover every token in the collection. Many thefts are a victim signing an approval, followed some time later by the approved address moving the tokens. The approval and the drain are separate transactions.
- Identify a token by its contract address, never by its name or symbol.
- Check which contract emitted an event before trusting what it says.
- Look for approvals that came before an unexpected outgoing transfer.