About ZCHAT

ZCHAT is a privacy-first encrypted messenger that sends chat messages as shielded Zcash transactions. Every message is end-to-end encrypted with zero metadata exposure. Built for the Zypherpunk Hackathon 2024-2025.

Demo Video

Implemented
In Progress
Planned

Core Protocol Features

ZMSG v4 Protocol

Conversation ID-based threading

Done
Private 1:1 Messaging

End-to-end encrypted via shielded transactions

Done
Message Chunking

Split large messages across multiple memos

Done
Contact Management

Save, nickname, and organize contacts

Done
Conversation History

Persistent chat history with threading

Done
ZEC Payments

Send payments with messages

Done
Read Receipts (ZRCPT)

Optional delivery confirmations

Done
Message Reactions (ZREACT)

React to messages with emoji

Done
Reply to Message (RPL)

Quote and reply to specific messages

Done
User Status (ZSTAT)

Set availability status

Done
Payment Requests (ZREQ)

Request ZEC from contacts

Done
Time-Locked Messages (ZTL)

Schedule, block-height, and conditional reveals

Done

Group Messaging (Sprint 4)

ZMSG-GROUP Protocol

Group messaging specification

In Progress
Group Creation

Create named groups with members

In Progress
Group Invitations

Invite users to join groups

In Progress
Group Messaging

AES-256-GCM encrypted group chat

In Progress
Leave Group

Exit groups with notification

In Progress
Group Settings

View members and group info

In Progress
Key Rotation

Rotate encryption keys when members leave

Planned
Admin Controls

Kick members, transfer ownership

Planned

Future Features

Encrypted Attachments

Images and audio files

Planned
Voice Messages

Encrypted voice recordings

Planned
iOS App

Native iOS client

Planned
Desktop App

macOS, Windows, Linux

Planned
Private Calls

Zcash-anchored live calls

Planned

Full protocol specification available in the source code repository