We described the benefits of using a TEE Multi-Prover for the OP Stack here. In this document, we will focus on how the TEE Prover could be used to assist with the external block production

Parties involved:

• Sequencer - L2 sequencer that may choose to order transactions or outsource the process to an external block builder
• Block Builder Sidecar - software that the sequencer runs to be able to outsource the block building process; the sidecar ensures the block received from a builder is correct and was built according to the specification
• External Block Builder - sophisticated actor who knows how to build valuable blocks
• TEE Prover network - a network of entities that verify the correctness of a block by relying on the guarantees provided by TEEs
• L1 Contract - where the updated state of the L2 is published

The diagram below shows the interactions between the parties when the Sequencer outsources the block building process to the External Block Builder

Workflow if block building is outsourced:

1. Sequencer authorizes the Sidecar to provide a block according to a specification
2. Sidecar requests the Block Builder to build a block according to the specification
3. Builder builds the block and returns it the Sidecar
4. Sidecar requests a proof from the TEE Prover Network to guarantee that the block was built correctly
5. The TEE Network Prover executes the block and verifies the correctness of the transactions. If the block is correct, a proof of execution is given to the Sidecar