Sequencer-Committee Interaction

When the Arbitrum sequencer intends to post a data batch using the Committee, it dispatches the data along with an expiration time to all Committee members in parallel via RPC. Each Committee member stores the data, signs the (hash, expiration time) pair using its BLS key, and returns the signature with a success indicator to the sequencer.

Once sufficient signatures are collected, the Sequencer aggregates them to create a valid DACert for the (hash, expiration time) pair. This DACert is then posted to the L1 inbox contract, making it accessible to the AnyTrust chain software at L2.

In cases where the Sequencer is unable to collect enough signatures within a designated timeframe, it resorts to a "fall back to rollup" strategy by posting the full data directly to the L1 chain. The L2 software is adept at comprehending both data posting formats (via DACert or full data) and handles each format appropriately.

In conclusion, AnyTrust, a groundbreaking innovation within the Offchain Labs ecosystem, represents a pivotal advancement in addressing the challenges of data availability, security, and cost efficiency in blockchain infrastructure. Through a judicious trust assumption and a novel approach to data posting, AnyTrust paves the way for more scalable, accessible, and secure blockchain solutions.