custom-note

Custom Note Contract

An Aztec Noir contract demonstrating how to create and use custom note types in the Aztec protocol.

Overview

This project showcases how to define a custom note structure with multiple fields and use it in a private smart contract. The contract stores custom notes in a private state that can only be viewed by the note owner.

Custom Note Structure

The CustomNote contains:

• a, b, c, d: Four arbitrary Field values for custom data
• randomness: A random Field value to ensure note privacy
• owner: The AztecAddress of the note owner

Contract Functions

insert(a: Field, b: Field, c: Field, d: Field)

A private function that creates and stores a new custom note.

• Parameters: Four field values (a, b, c, d)
• Behavior: Creates a note with the provided values and assigns ownership to the message sender
• Privacy: Emits the note using unconstrained onchain message delivery

view_custom_notes(owner: AztecAddress)

An unconstrained utility function to view all custom notes for a given owner.

• Parameters: Owner's Aztec address
• Returns: Array of custom notes (up to MAX_NOTES_PER_PAGE)
• Usage: Can be called to query notes without consuming gas

Building

Compile the contract using the Aztec CLI:

aztec compile

Usage Example

1. Deploy the contract to an Aztec network

2. Insert a custom note:

CustomNote.insert(field1, field2, field3, field4)

3. View notes for an address:

CustomNote.view_custom_notes(owner_address)

Key Features

• Demonstrates custom note type implementation with the #[note] macro
• Shows how to use PrivateSet storage for managing multiple notes per user
• Implements proper note privacy using randomness
• Provides getter methods for accessing individual note fields

Dependencies

• Aztec v5.0.0-rc.1

To set this version:

aztec-up 5.0.0-rc.1

Project Structure

custom-note/
├── Nargo.toml           # Project configuration
└── src/
    ├── main.nr          # Main contract implementation
    └── custom_note.nr   # Custom note type definition

Learn More

• Aztec Documentation
• Noir Language Documentation