[Don't merge until multichain released to testnet] Multichain overview and architecture

docs/products/eigenlayer/developers/concepts/avs-contracts.md

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docs/products/eigenlayer/developers/concepts/avs-keys.md

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docs/products/eigenlayer/developers/concepts/avs-security-models.md

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docs/products/eigenlayer/developers/concepts/multichain/_category_.json

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+  "position": 5,
+  "label": "Multichain"
+}

docs/products/eigenlayer/developers/concepts/multichain/multichain-architecture.md

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+---
+sidebar_position: 2
+title: Architecture
+---
+
+The Multichain Verification framework uses the core contracts and templates in EigenLayer middleware described in the table. 
+These are not pluggable and are intended to interface with offchain, modular components. 
+
+| Contract Name                 | Deployment Target     | Deployer                 | Description                                                                                                                                                                            |
+|-------------------------------|-----------------------|--------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| **`KeyRegistrar`**            | Ethereum Singleton    | EigenLayer Core Protocol | Unified module for managing and retrieving BN254 and ECDSA cryptographic keys for Operators with built-in key rotation support, extensible to additional curves like BLS381            |
+| **`CrossChainRegistry`**      | Ethereum Singleton    | EigenLayer Core Protocol | Manages AVS multichain configuration and tracks deployment addresses when using EigenLayer's generation and transport mechanisms                                                       |
+| **`OperatorTableCalculator`** | Ethereum, One per AVS | AVS Middleware           | Required middleware contract deployed by an AVS for specifying stake weights per asset, or implementing custom logic like stake capping                                                |
+| **`OperatorTableUpdater`**    | One per target chain  | EigenLayer Core Protocol | Parses and verifies the global Stake Table Root and rehydrates individual Operator tables in the `CertificateVerifier`                                                                 |
+| **`CertificateVerifier`**     | One per target chain  | EigenLayer Core Protocol | Enables AVS consumers to verify tasks against operator sets using transported stake tables. The `CertificateVerifier` is the single integration point between AVSs and their consumers |
+
+## CertificateVerifier 
+
+The `CertificateVerifier` is the core contract that AVSs need to integrate with. It is the gateway to EigenLayer services (that is, where offchain services come onchain) and 
+is deployed on every supported chain. 
+
+The `CertificateVerifier` has a stable, chain-agnostic integration pattern. You interact with the same 
+interface regardless of which chain you're deploying to, or which consumers are using your AVS. This enables a “code once, 
+deploy everywhere” workflow that reduces cross-chain complexity, eases integration with other AVSs, and simplifies ongoing maintenance.
+
+## Contract Interaction
+
+The contracts interact as illustrated.
+
+```mermaid
+classDiagram 
+direction TD
+namespace Ethereum{
+    class AVS {
+        AVSRegistrar
+    }
+    class OperatorTableCalculator {
+        StakeCapping
+        StakeWeighting (Multiplier, Oracle)
+        ProtocolVotingPowerCalc
+    }
+    class StakeGeneration {
+        crossChainRegistry
+        KeyRegistrar
+  }   
+}
+namespace TargetChain{
+    class AVSConsumer {
+      requests Operator task 
+      receives cert ()
+    }
+    class CertificateVerifier{
+      n Operator Tables
+     verifyCert (bool)
+ }
+}
+
+namespace Offchain{
+  class Operator {
+   consumer input
+   return certificate()
+  }
+}
+
+AVS --> OperatorTableCalculator : Deploys Operator Table Calculator
+StakeGeneration --> OperatorTableCalculator : Calculates Operator Tables
+Stake Generation --> transport : Transports Stake Table
+transport --> CertificateVerifier : Updates stakes and Operator Status
+AVSConsumer --> Operator : requests task
+Operator --> AVSConsumer: creates cert
+AVSConsumer --> CertificateVerifier : verifies certificate
+```

docs/products/eigenlayer/developers/concepts/multichain/multichain-overview.md

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+---
+sidebar_position: 1
+title: Overview
+---
+
+:::note
+Multichain implements [ELIP-008 EigenLayer Multichain Verification](https://github.com/eigenfoundation/ELIPs/blob/elip-008v1/ELIPs/ELIP-008.md) and is available on testnet in v1.7.0.
+:::
+
+Multichain verification enables AVSs to operate across multiple chains and maintain the security guarantees of EigenLayer.
+The multichain verification framework uses standardized infrastructure for key management, stake verification, and certificate
+validation.
+
+## Components 
+
+The components that enable multichain verification are:
+
+| **Component**                   | **Description**                                                                                                                                                                                                                                     |
+|--------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| **Operator Table**             | Represents stake-weighted Operator delegations and allocations of a given Operator Set.                                                                                                                                                             |
+| **Stake Table**                | Represents the global view of all Operator Sets with AVS-decorated stake weights. One Stake Table is deployed on each target chain and represents many Operator Tables.                                                                             |
+| **Stake Weighting & Table Calculation** | An `OperatorTableCalculator` is provided for AVSs to enable custom stake weighting of different assets and to apply the formats required by the Operator Table.                                                                                     |
+| **Certificates & Certificate Verification** | Signed Operator outputs (certificates), and a provided core contract (`CertificateVerifier`) for verifying those outputs against the Operator Table and stake-weighted rules (for example, signed weight above nominal or proportional thresholds). |
+| **Stake Generation & Transport** | Specification for generating and verifying the global Stake Table Merkle root and transporting it to core contracts on many chains. EigenLabs operates a Transporter for testnet. The Transporter is permissionless and pluggable.                  |
+
+## Process
+
+To have a single global root with up-to-date stake representation on multiple chains where an AVS is used: 
+
+1. The AVS writes and deploys the logic for calculating its single, weighted Operator Table (or uses the default logic).
+2. EigenLayer combines the many Operator Set representations to generate a global stake table.
+3. The global stake table is transported to target chains. The Operator Tables are then used for verifying Operator certificates.
+4. Weekly, or as forcible updates are needed (for example, when an Operator is ejected or slashed), the table is regenerated and transported again.

docs/products/eigenlayer/developers/concepts/task.md

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