> Aztec.nr API reference, v6.0.0 (mainnet and testnet). Index: https://docs.aztec.network/aztec-nr-api/v6.0.0/llms.txt

# Module get_membership_witness

Module: `noir_aztec::oracle::get_membership_witness`

## Functions

- [are_block_hashes_in_archive](/aztec-nr-api/v6.0.0/noir_aztec/oracle/get_membership_witness/fn.are_block_hashes_in_archive.md): Returns whether each block hash is present in the archive tree whose root is defined in `anchor_block_header`.
- [get_block_hash_membership_witness](/aztec-nr-api/v6.0.0/noir_aztec/oracle/get_membership_witness/fn.get_block_hash_membership_witness.md): Returns a membership witness for a `block_hash` in the archive tree whose root is defined in `anchor_block_header`.
- [get_maybe_block_hash_membership_witness](/aztec-nr-api/v6.0.0/noir_aztec/oracle/get_membership_witness/fn.get_maybe_block_hash_membership_witness.md): Same as [`get_block_hash_membership_witness`](/aztec-nr-api/v6.0.0/noir_aztec/oracle/get_membership_witness/fn.get_block_hash_membership_witness.md), but returns `None` instead of erroring when the block is not present in the archive tree. Intended for callers that need to handle absence (e.g. existence checks via `.is_some()`).
- [get_note_hash_membership_witness](/aztec-nr-api/v6.0.0/noir_aztec/oracle/get_membership_witness/fn.get_note_hash_membership_witness.md): Returns a membership witness for a `note_hash` in the note hash tree whose root is defined in