Interchain Standards (ICS) for the Cosmos network & interchain ecosystem.
IBC Interchain Standards
Synopsis
This repository is the canonical location for development and documentation of the inter-blockchain communication protocol (IBC).
It shall be used to consolidate design rationale, protocol semantics, and encoding descriptions for IBC, including both the core transport, authentication, & ordering layer (IBC/TAO) and the application layers describing packet encoding & processing semantics (IBC/APP).
Contributions are welcome. See CONTRIBUTING.md for contribution guidelines.
What is IBC?
For a high-level explanation of what IBC is and how it works, please read this blog post.
Interchain Standards
All standards at or past the "Draft" stage are listed here in order of their ICS numbers, sorted by category.
IBC v2 Specifications
IBC v2 is the latest iteration of the IBC protocol. It streamlines the integration of IBC by removing the connection and channel handshake layers in favor of direct client-to-client packet flow. For an overview, see the IBC v2 introduction.
Core Transport
| Interchain Standard Number | Standard Title | Stage | Implementations | Maintainer | | -------------------------- | -------------- | ----- | --------------- | ---------- | | 2 | Client Semantics | Draft | ibc-go | Protocol team | | 4 | Packet Semantics | Draft | ibc-go | Protocol team | | 5 | Port Allocation | Draft | ibc-go | Protocol team | | 24 | Host Requirements | Draft | ibc-go | Protocol team | | 26 | IBC Application Callbacks | Draft | ibc-go | Protocol team |
App
| Interchain Standard Number | Version | Standard Title | Stage | Implementations | Maintainer | | -------------------------- | ------- | -------------- | ----- | --------------- | ---------- | | 27 | v2 | General Message Passing | Draft | ibc-go | Protocol team |
IBC v1 Specifications
IBC v1 is the original version of the protocol. It establishes cross-chain communication through connection and channel handshakes before applications can exchange packets.
Meta
| Interchain Standard Number | Standard Title | Stage | Maintainer | | ---------------------------------------- | -------------------------- | ----- | ------------- | | 1 | ICS Specification Standard | N/A | Protocol team |
Core Transport
| Interchain Standard Number | Standard Title | Stage | Implementations | Maintainer | | ------------------------------------------------------------- | -------------------------- | --------- | --------------- | ------------- | | 2 | Client Semantics | Candidate | ibc-go, ibc-rs | Protocol team | | 3 | Connection Semantics | Candidate | ibc-go, ibc-rs | Protocol team | | 4 | Channel & Packet Semantics | Candidate | ibc-go, ibc-rs | Protocol team | | 5 | Port Allocation | Candidate | ibc-go | Protocol team | | 23 | Vector Commitments | Candidate | ibc-go, ibc-rs | Protocol team | | 24 | Host Requirements | Candidate | ibc-go, ibc-rs | Protocol team | | 25 | Handler Interface | Candidate | ibc-go, ibc-rs | Protocol team | | 26 | Routing Module | Candidate | ibc-go, ibc-rs | Protocol team | | 33 | Multi-hop Messaging | Candidate | ibc-go | Protocol team |
Light Clients
| Interchain Standard Number | Standard Title | Stage | Implementations | Maintainer | | --------------------------------------------------------------- | -------------------------- | ----- | --------------- | ------------- | | 6 | Solo Machine Client | Candidate | ibc-go | Protocol team | | 7 | Tendermint Client | Candidate | ibc-go, ibc-rs | Protocol team | | 8 | Wasm Client | Candidate | ibc-go, ibc-rs | Protocol team / Composable Finance | | 9 | Loopback Client | Draft | ibc-go | Protocol team | | 10 | GRANDPA Client | Draft | | Octopus Network |
Relayer
| Interchain Standard Number | Standard Title | Stage | Implementations | Maintainer | | ---------------------------------------------------------------- | -------------------------- | ----- | --------------- | ------------- | | 18 | Relayer Algorithms | Finalized | go-relayer, rust-relayer, ts-relayer | Protocol team |
App
| Interchain Standard Number | Version | Standard Title | Stage | Implementations | Maintainer | | -------------------------------------------------------- | ------- | ----------------------- | --------- | ------------------------------------------------------------------------------------------------------------------------- | ------------------ | | 20 | v1 | Fungible Token Transfer | Candidate | ibc-go, ibc-rs | Protocol team | | 20 | v2 | Fungible Token Transfer | DEPRECATED | | Protocol team | | 27 | v1 | Interchain Accounts | Candidate | ibc-go | Protocol team | | 28 | v1 | Cross-Chain Validation | Candidate | interchain-security | Cosmos Hub team | | 29 | v1 | General Relayer Incentivization Mechanism | DEPRECATED | | Protocol team | | 30 | v1 | IBC Application Middleware | N/A | N/A | Protocol team | | 31 | v1 | Cross-Chain Queries | Draft | N/A | Protocol team | | 32 | v1 | Interchain Queries | Candidate | async-icq | Strangelove Ventures | | 100 | v1 | Interchain Atomic Swap | Candidate | ibcswap | Side Labs | | 721 | v1 | Non-Fungible Token Transfer | Candidate | nft-transfer | IRIS Network |
Translations
The Interchain Standards are also translated into the following languages:
