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# System prepended metadata

title: RFC Meeting - Milestone Merkle Validation - 2020-05-18

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# RFC Meeting - Milestone Merkle Validation - 2020-05-18

https://github.com/iotaledger/protocol-rfcs/pull/12

## Participants

- Thibault Martinez
- Gal Rogozinski
- Luca Moser
- Wolfgang Welz
- Hans Moog

## Goals

- Review the RFC PR;
- Agree/disagree on its content;
- Make progress towards merging it;

## Discussion topics


### Steps to get the RFC merged
- If you have no objections, give approval review.
- This takes precedence over non-critical tasks.
- Change the current spec to: Only non-0-value state mutating transactions are included in the merkle tree for completeness.
- Thibault will validate the exmaple implementation.
- Remove unresolved question(s) - make the decision part of the implementation.


### Drawback discussion
- Merkle tree depth limit
- Slightly more expensive merkle tree computation & validation more expensive

### Unresolved questions 
- Merkle tree hash computation hashing algorithm
    - Blake2 (Go for this one)
    - SHA256 (Not doing this)
    - Troika/Kerl (Not doing this)

### Changes to validation (to resolve)
- Should we exlude 0 value transactions from the merkle validation? This removes the proof of inclusion capability for the current Mainnet. This can actually still be done just providing the path to a milestone. 
- The RFC will be changed so that only state mutating transactions are included when computing the merkle tree hash.




