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Using Address Note in Aztec.nr

Address notes hold one main property of the type AztecAddress. It also holds owner and randomness, similar to other note types.

AddressNote​

This is the AddressNote:

address_note_def
#[note]
#[derive(Eq)]
pub struct AddressNote {
    address: AztecAddress,
    owner: AztecAddress,
    randomness: Field,
}

impl AddressNote {
    pub fn new(address: AztecAddress, owner: AztecAddress) -> Self {
        // Safety: we use the randomness to preserve the privacy of the note recipient by preventing brute-forcing, so a
        // malicious sender could use non-random values to make the note less private. But they already know the full
        // note pre-image anyway, and so the recipient already trusts them to not disclose this information. We can
        // therefore assume that the sender will cooperate in the random value generation.
        let randomness = unsafe { random() };
        AddressNote { address, owner, randomness }
    }
}
Source code: noir-projects/aztec-nr/address-note/src/address_note.nr#L5-L24

Importing AddressNote​

In Nargo.toml​

address_note = { git="https://github.com/AztecProtocol/aztec-packages/", tag="v0.81.0", directory="noir-projects/aztec-nr/address-note" }

In your contract​

addressnote_import
use dep::address_note::address_note::AddressNote;
Source code: noir-projects/noir-contracts/contracts/escrow_contract/src/main.nr#L14-L16

Working with AddressNote​

Creating a new note​

Creating a new AddressNote takes the following args:

  • address (AztecAddress): the address to store in the AddressNote
  • owner (AztecAddress): owner is the party whose nullifying key can be used to spend the note
addressnote_new
let note = AddressNote::new(owner, owner);
Source code: noir-projects/noir-contracts/contracts/escrow_contract/src/main.nr#L28-L30

In this example, owner is the address and the npk_m_hash of the donor was computed earlier.

Learn more​