What is Aggregator?

When there are multiple messages each signed with distinct keys, an Aggregator has the capability to create a unified, verified signature. This consolidated signature indicates the validity of all individual signatures within the group.

Aggregators facilitate efficiency by merging several signatures into one. This process aids in conserving data availability, allowing multiple UserOperations to be authenticated simultaneously in a streamlined manner.

For certain accounts that are compatible with specific types of signatures amenable to aggregation (such as BLS signatures), the responsibility for verifying the account's signature is transferred to an external contract. This contract then only needs to verify a single, collective signature for an entire bundle of operations.

Aggregator

For a deeper understanding of the significance of signature aggregation, consider exploring Vitalik Buterin's perspectives on the topic here.

Sources: Ethereum, ERC4337.io, Alchemy