Interchain accounts and Cascade

• A DeFi protocol on Injective can store trade receipts permanently on Cascade.
• An NFT marketplace on Osmosis can use Cascade for immutable media storage.
• A DAO on the Cosmos Hub can archive governance proposals.

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How it works

1. The controller chain submits MsgSendTx containing a packed MsgRequestAction.
2. The IBC relayer delivers the packet to Lumera, the host chain.
3. Lumera’s ICA host module unpacks and executes the MsgRequestAction.
4. An ICA address on Lumera pays the escrow fee. It must be pre-funded.
5. The action is registered on-chain with an action_id.
6. The application uploads the file directly to the SN-API, the HTTP API served by SuperNodes, using the action_id.

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Application-level keypairs

• The application generates a keypair on the controller side.
• The public key is included in the action registration.
• The private key signs file uploads to the SN-API.
• This separates the control plane (IBC messages) from the data plane (file transfers).

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ICA helpers in the Go SDK

import "github.com/LumeraProtocol/sdk-go/client"

// Pack a MsgRequestAction for ICA submission
packedMsg := client.PackRequestForICA(msg)

// Pack a MsgApproveAction for ICA submission
packedApprove := client.PackApproveForICA(approveMsg)

// Extract action IDs from the IBC acknowledgement
actionIDs := client.ExtractRequestActionIDsFromAck(ackData)

cfg := &client.Config{
    ICAOwnerKeyName: "ica-controller-key",
    ICAOwnerHRP:     "cosmos", // Bech32 prefix of the controller chain
}

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The ICA client CLI

# Upload a file via ICA
lumera-ica-client upload --file document.pdf --controller-chain cosmos

# Check action status
lumera-ica-client action status --action-id <id>

# Download a file
lumera-ica-client download --action-id <id>

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Security considerations

• Control plane isolation. IBC messages carry only metadata and fee escrow. File data never touches the IBC channel.
• Data plane authentication. File uploads to the SN-API use application-level signatures, independent of the ICA address.
• Fee pre-funding. The ICA address must hold ulume before registering actions. Monitor its balance to prevent failed registrations.

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Next steps