# INTERCHAIN BRIDGE

**Basic Interchain Transaction Lifecycle**

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<summary><mark style="color:blue;">1. User Initiates Action</mark></summary>

A user triggers an on-chain transaction on a zone chain (e.g., DeFiChain, Partisia or Polygon) such as transferring tokens, submitting a proposal, or interacting with a bridge. This initiates a multi-chain intent, which is captured by a registered Interchain operator.

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Basic Interchain Transaction Lifecycle

#### <mark style="color:blue;">1. User Initiates Action</mark>

A user triggers an on-chain transaction on a zone chain (e.g., DeFiChain, Partisia or Polygon) — such as transferring tokens, submitting a proposal, or interacting with a bridge. This initiates a multi-chain intent, which is captured by a registered Interchain operator.

#### <mark style="color:blue;">2. Operator Prepares Partial Block</mark>

The operator (e.g., Crypto Factor Bridge) splits the transaction into logical execution parts — for example:

* Lock tokens on the source chain
* Release tokens on the destination chain

These are submitted to the partial chain mempool, ready for processing.

#### <mark style="color:blue;">3. Oracle Layer Fetches and Merges Mempools</mark>

The Oracle Layer, a distributed network of Nodes, collects partial blocks and submits them to the Interchain master mempool on Partisia Blockchain.

It includes:

* Zone chain block hashes
* Transaction proofs
* Execution metadata

This step ensures all zone data is traceable and cryptographically verifiable.

#### <mark style="color:blue;">4. Master Chain Proposes a Block</mark>

The Interchain Master Chain (on PBC) compiles a proposed block that includes all valid partial chain transactions.

This block:

* References zone chain IDs
* Includes Merkle roots of validated execution parts
* Sets up a unified state view for all connected chains

#### <mark style="color:blue;">5. Validation & ZK Signing</mark>

The proposed block undergoes multi-layer validation:

* EVM block verification
* Zone consensus checks
* Master chain validation

It is then signed using MPC-ZK signatures, ensuring zero-knowledge proof of validity without exposing sensitive details.

#### <mark style="color:blue;">6. Master Block is Finalised</mark>

The now signed and validated master block becomes the latest state of the Interchain.

It is:

* Immutable after confirmation threshold
* Stored on PBC
* The source of truth for all zone chains to derive execution updates

#### <mark style="color:blue;">7. Oracle Commits Partial Blocks Back to Zone Chains</mark>

Using Merkle proofs and ZK signatures, the Oracle Layer commits finalised Partial Blocks to their respective zone chains.

Each commitment includes:

* Block hash of the master chain
* Proof-of-finalisation for the partial block
* Timestamp and execution queue triggers

#### <mark style="color:blue;">8. Execution Queue is Triggered</mark>

Each zone chain activates its execution queue, which reads the confirmed execution parts and processes them:

* Token releases
* Governance updates
* State changes

Reverts are also handled if conditions were unmet or invalid.

#### <mark style="color:blue;">9. Operator Updates Protocol State</mark>

Operators update smart contract states to reflect the finalised transaction result. This could include:

* Emitting events
* Updating balances
* Triggering follow-up actions in the protocol logic

#### <mark style="color:blue;">10. User Receives Confirmation</mark>

The user’s wallet or interface reflects the result — such as tokens received or action confirmed — completing the cross-chain transaction cycle.

All steps are executed trustlessly, without central relayers or third-party dependencies.