Validator
A validator is a node operator that verifies transactions, executes on-chain finalize logic, and produces blocks on the Aleo network. Validators run SnarkOS and participate in a proof-of-stake consensus protocol. They must bond Aleo credits to be eligible for block production.
Aleo validators do not re-execute the full computation of every transaction. They verify the zero-knowledge proof that accompanies each transaction, which is lightweight compared to replaying the computation. This confirms the user executed the program correctly without revealing private inputs. Validators do, however, execute the final { } portions of transactions that handle public state updates to mappings.
Validators take turns proposing blocks. The selected validator aggregates verified transactions, applies finalize state changes, and broadcasts the block. Other validators confirm it and update their local state. Validators earn transaction fees for their work. Misbehavior (invalid blocks, going offline during a turn) can result in slashed stakes.