Stream Checkpointing is how Towns Protocol ensures data integrity of a stream on a secure L2 blockchain. This guide provides an in-depth understanding of the process, focusing on the mini block headers, their structure, and their role in the Towns Protocol.

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Mini Block Headers

Mini block headers serve as a compact summary of a mini block’s contents, providing essential information needed to verify the integrity and finality of transactions within the Towns Protocol.

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Components of a Mini Block Header

A mini block header is an event that encapsulates several critical pieces of information:
  1. Hash of Previous Mini Block Header: This links mini blocks in a chain, ensuring continuity and traceability.
  2. Hashes of Events: These are references to the events included in the current mini block, acting as a summary of the block’s content.
  3. Snapshots (0-1): Optional snapshots may be included for additional context or state information. [see Snapshotting]
  4. Vote Proof: Evidence of consensus from participating nodes, confirming the validity of the mini block’s contents.
  5. Signature: The entire event is signed by the elected leader node, adding an additional layer of security and authenticity.

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Storage and Distribution

  • Local Storage by Nodes: Each node participating in the Towns Protocol stores the mini block headers locally. This storage plays a critical role in maintaining the network’s integrity and redundancy.
  • Sent to Clients: Mini block headers are also transmitted to clients, providing them with the necessary information to verify transaction finality and integrity.

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Finality and Verification

Understanding the finality of transactions within the Towns Protocol is crucial for maintaining trust in the system. The mini block header plays a central role in this process:
  • Transaction Finality: If a client or node possesses a mini block header and observes a transaction on the Towns Chain with the same header hash, the transaction can be considered final.
  • Verification Process: The interconnected nature of the mini block headers, along with the consensus proof and node signatures, allows for a robust verification process, ensuring the authenticity and integrity of the data within the Towns Protocol.