6.2 Data Structure and Storage

The Public Registry uses two primary data structures for efficient storage and querying:

1. Scope & Record Hash based Categories Storage:

   • Implemented as:

     mapping(uint256 scope => EnumerableMap.Bytes32ToBytes32Map RecordToCategory) scopeRecordCategories

     • enables quick lookup of category bitmaps for a given record hash within a specific scope
     • uint256 scope is the scope identifier
     • EnumerableMap.Bytes32ToBytes32Map RecordToCategory is a mapping of record hashes to category bitmaps
     • EnumerableMap.Bytes32ToBytes32Map is imported from the EnumerableMap openzeppelin library
     • EnumerableMap.Bytes32ToBytes32Map is utilised for easy iteration over the set of record hashes.

2. Scope based Record Merkle Trees:

   • Implemented as

     mapping(uint256 scope => LeanIMTData recordTree) scopeRecordTrees

     • Supports inclusion proof verification for a given record hash within a specific scope
     • uint256 scope is the scope identifier
     • LeanIMTData recordTree is the merkle-tree representation of the set of record hashes within the scope
     • LeanIMTData is imported from the InternalLeanIMT zk-kit library
     • InternalLeanIMT, LeanIMTData provides a gas-optimized merkle-tree implementation.