Open HRMP channel between Shiden Network and Crab Parachain


We propose to open HRMP communication between Shiden Network and Crab Parachain. This will require actions on both chains.


We propose to open a bi-directional channel between Shiden Network and Crab Parachain. The primary use cases will be:

  1. CRAB token can be transferred to Shiden to be used in the ecosystem of Shiden Network and the protocols build on top of the network.


There is no on-chain proposal. The proposal created in this forum acts as an official proposal between Crab Parachain and Shiden Network.

Technical details

The procedure for opening the channels is as follows:

  1. Crab Parachain initializes a proposal to open Crab Parachain ****to the Shiden Network HRMP channel via the Astar forum.
  2. Wait until the proposal on step 1 gets approved & enacted.
  3. Onboard your testnet on the Rococo relay chain and exchange public endpoints and parachain-ids.
  4. Wait until onboarding was successful on testnet.
  5. Shiden Network proposes to accept the Crab Parachain to Shiden Network HRMP channel and open an Shiden Network to Crab Parachain HRMP channel via [Astar MuliSig Governance Batch call].
  6. Wait until the proposal on step 5 gets approved & enacted.
  7. Crab Parachain accepts the Shiden Network to Crab Parachain HRMP channel.
  8. Wait for another session on Kusama for the change to be effective.

These extrinsics need to be called with the parachain’s sovereign account as the origin. To achieve this, on the Crab Parachain side we will use polkadot-xcm pallet to send XCM message to the relay chain, by executing the following extrinsic from the parachain. Shiden Network should make an open request call and an accept request call with its pallet.

As a prerequisite, the parachain’s sovereign account must contain at least 10 KSM to be locked as collateral (5 for each channel direction), plus some KSM to pay for XCM execution fees.


  1. Request to open HRMP channel with Crab Parachain:

    hrmp.hrmpInitOpenChannel(recipient: 2105, proposedMaxCapacity: 1000, proposedMaxMessageSize: 102400)

  2. Accept the request from Crab Parachain to open HRMP channel:

    hrmp.hrmpAcceptOpenChannel(sender: 2105)

Assumption: Crab Parachain requests to open channel with Shiden

About Crab Parachain:

Crab Network (Crab) is a canary network with real economic value for Darwinia, positioning similar to Polkadot’s Kusama Network, which is a programmable cross-chain platform for Dapps. It is substrate-based, EVM-compatible, and connected to Kusama. Crab Network contains three chains, namely Crab Chain(CC), Crab Smart Chain(CSC), and Crab Parachain(CP). CC and CSC provide two sets of different interfaces and chain structures but share the same nodes network, state storage, and native token(CRAB).

As a parachain on the Kusama Network, Crab Parachain benefits from the shared security of the Kusama Relay Chain. Now, it has integrated with other parachains connected to Kusama, and connected to CC via LCMP.


The only use-case is to add CRAB token in our ecosystem?
Any other unique use-cases we can work on together?


  1. CRAB token will be available to deposit and use on Shiden Network, meanwhile, Shiden’s native token(SDN) and ecosystem assets to Crab Network will integrated with Crab ecosystem’s DeFi products via the routing protocol very soon.
  2. The XCM integration between Crab Parachian and Shiden will bring the Crab Network with the active developer ecosystems, while Shiden can also take advantage of Darwinia Universal Cross-Chain Messaging SDK to implement cross-chain development. Darwinia Universal Cross-Chain Messaging SDK is a solidity library that provides the easiest way for decentralized applications to become cross-chain applications. The SDK abstracts away the technical bits of LCMP and other cross-chain protocols for developers, reducing the level of difficulty required to use them. It allows developers to focus on integrating only the capabilities they need, from the blockchains that provide them. In addition to the LCMP that has been successfully developed, Darwinia, as a universal cross-chain messaging infrastructure, will also support a variety of messaging protocols, such as XCMP, ROLLUP, etc. Through the SDK, the Dapps on Shiden will be able to easily transact across heterogeneous chains inside and outside the Kusama ecosystem, which will bring full interoperability between multiple chains.

Thanks a lot for your feedback!
Looking more into this cc @RyoT