ergoplatform/ergo

Add proof that interlink vector corresponds to its header

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#1,384 opened on Jun 4, 2021

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Description

Implement batch Merkle proof for multiple keys (in scrypto), and use it to prove that interlink vector is indeed corresponding to its header (add it to json/binary representation of PoPoW header, add checks to the verifier).

Interlink vector (links to super-blocks of different levels in the past) is stored in extension section of a block in packed form,

So the proof generation and verification would be as following:

  • add batchProofFor(keys: Array[Byte])* to ExtensionCandidate to get batch proof for possibly many keys

  • in NipopowAlgos, instead of proofForInterlink (which can be removed), make proofForInterlinkVector(ext: ExtensionCandidate) to get batch Merkle proof for all the interlinks in the extension (so keys starting with InterlinksVectorPrefix)

  • add batch proof to PoPowHeader, and make there method to check it (note: pack the vector before the check), fix serialization accordingly

  • implement hasValidProofs which is checking proofs for all the PoPoWHeader instances

  • do tests on the way :)

Contributor guide

Research direction
Study the current ExtensionCandidate and InterlinkVector implementation, then understand batch Merkle proofs in the Scrypto library. Implement batchProofFor in ExtensionCandidate, create proofForInterlinkVector in NipopowAlgos, add batch proof to PoPowHeader, implement hasValidProofs, and write tests.
Tech stack
scala
Domain
blockchain
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Scala
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30