Migrating to permissionless fault proofs on OP Stack

pages/operators/chain-operators/tools/op-challenger.mdx

@@ -189,7 +189,7 @@ This guide provides a walkthrough of setting up the configuration and monitoring
 
   ```bash
   ./op-challenger/bin/op-challenger \
-    --trace-type cannon \
+    --trace-type permissioned,cannon \
     --l1-eth-rpc http://localhost:8545 \
     --rollup-rpc http://localhost:9546 \
     --game-factory-address $DISPUTE_GAME_FACTORY \

pages/operators/chain-operators/tutorials.mdx

@@ -38,6 +38,8 @@ This section provides information on adding attributes to the derivation functio
 
   <Card title="Integrating a new da layer with alt Da" href="/operators/chain-operators/tutorials/integrating-da-layer" />
 
+  <Card title="Migrating to permissionless fault proofs on OP Stack" href="/operators/chain-operators/tutorials/migrating-permissionless" />
+
   <Card title="Modifying predeployed contracts" href="/operators/chain-operators/tutorials/modifying-predeploys" />
 
   <Card title="Using viem" href="/app-developers/get-started" />

pages/operators/chain-operators/tutorials/_meta.json

@@ -4,5 +4,6 @@
     "adding-precompiles": "Adding a precompile",
     "modifying-predeploys": "Modifying predeployed contracts",
     "integrating-da-layer": "Integrating a new DA layer",
+    "migrating-permissionless": "Migrating to permissionless fault proofs on OP Stack",
     "chain-dev-net": "Running a local network environment"
 }

pages/operators/chain-operators/tutorials/migrating-permissionless.mdx

@@ -0,0 +1,306 @@
+---
+title: Migrating to permissionless fault proofs on OP Stack
+description: A high-level guide for transitioning from permissioned to permissionless fault proofs on an OP Stack.
+lang: en-US
+content_type: tutorial
+topic: migrating to permissionless fault proofs on OP Stack
+personas:
+  - chain-operator
+categories:
+  - fault proofs
+  - smart contracts upgrades
+  - Superchain-shared contracts
+  - proof system
+  - OPCM upgrade
+  - OPCM contracts
+  - dispute game
+is_imported_content: 'false'
+---
+
+import { Callout } from 'nextra/components'
+
+# Migrating to permissionless fault proofs on OP Stack
+
+This guide provides a high-level overview for chain operators looking to transition their OP Stack from permissioned to permissionless fault proofs. It's designed to be accessible for technical decision makers while providing sufficient detail for implementation teams.
+
+## Overview
+
+The OP Stack architecture uses Fault Proofs to ensure the validity of withdrawals from L2 to L1.
+The validity of transactions on L2 is handled by the node's consensus rules.
+Transitioning from permissioned to permissionless proofs represents a significant security upgrade, allowing any participant to propose and challenge state output roots.
+Permissioned games previously relied on a single trusted validator—typically the proposer configured in the `PermissionedDisputeGame`, usually the network's only sequencer.
+
+This migration involves several key components:
+
+*   Configuring security-critical dispute [monitoring services](/operators/chain-operators/tools/chain-monitoring)
+*   Deploying and configuring smart contracts using [op-deployer](/operators/chain-operators/tools/op-deployer)
+*   Testing the new system before activation
+*   Setting the respected game type to permissionless fault proofs, specifically using the `FaultDisputeGame`
+
+## Prerequisites
+
+Before beginning this transition, your chain should:
+
+*   Be running a standard OP Stack implementation
+*   Be operating with the recommended infrastructure services including [`op-challenger`](/stack/fault-proofs/challenger) and [`op-dispute-mon`](/operators/chain-operators/tools/chain-monitoring#dispute-mon)
+
+## 1. Configure the dispute components
+
+The `op-challenger` and `op-dispute-mon` services are critical security components that participate in the dispute game process to challenge invalid proposals and monitor active games.
+
+### Upgrade to the latest `op-challenger`
+
+Upgrade to the [latest release](https://github.com/ethereum-optimism/optimism/releases), which contains important improvements to simplify the upgrade process.
+
+```bash
+# Example upgrade command (implementation may vary based on your deployment)
+git clone https://github.com/ethereum-optimism/optimism -b op-challenger/v1.3.3 --recurse-submodules
+cd optimism
+make op-challenger
+```
+
+### Update network configuration
+
+Configure `op-challenger` to load your chain configuration. Even if your chain is not included in the [superchain-registry](/superchain/superchain-registry), you can specify a custom configuration:
+
+```bash
+# For chains in the registry
+--network <chain-name>
+
+# For chains not in the registry, provide a path to your rollup configuration
+--network-config /path/to/your/network-config.json
+```
+
+### Enable cannon trace type
+
+Configure `op-challenger` to support both permissioned and permissionless games by setting:
+
+```bash
+--trace-type permissioned,cannon
+```
+
+Or by setting the environment variable:
+
+```
+OP_CHALLENGER_TRACE_TYPE=permissioned,cannon
+```
+
+### Configure prestates access
+
+Replace the `--cannon-prestate` flag with `--prestates-url`, which points to a source containing all required prestates:
+
+```bash
+--prestates-url <URL_TO_PRESTATES_DIRECTORY>
+```
+
+The URL can use `http`, `https`, or `file` protocols. Each prestate should be named as `<PRESTATE_HASH>.json` or `<PRESTATE_HASH>.bin.gz`.
+
+### Building required prestates for chains not in the Superchain Registry
+
+You'll need at least two prestates:
+
+1.  The prestate currently used for permissioned games
+2.  A new prestate matching the `faultGameAbsolutePrestate` configuration for permissionless games
+
+<Callout type="info">
+  The prestate used for permissioned games typically doesn't include the necessary chain configuration for permissionless fault proofs.
+  When deploying a new chain, you must first deploy the contracts and then generate the correct chain configuration.
+  As a result, the original permissioned prestate usually isn't suitable for permissionless operation.
+  Therefore, it's common practice to generate and maintain two separate prestates.
+  The challenger will need access to both in order to properly monitor existing permissioned games and newly activated permissionless games.
+</Callout>
+
+For chains not in the Superchain Registry, you need to build custom prestates with your chain's configuration:
+
+```bash
+git clone https://github.com/ethereum-optimism/optimism --recurse-submodules
+cd optimism
+
+# To build a specific prestate (e.g., for op-program/v1.5.0)
+git checkout op-program/v1.5.0
+make reproducible-prestate
+
+# Generate the prestate with your chain's specific configuration
+./op-program/bin/op-program \
+  --l2.genesis /path/to/your/l2-genesis.json \
+  --rollup.config /path/to/your/rollup-config.json \
+  --network.l2chainid <YOUR_L2_CHAIN_ID> \
+  --exec.prestate
+```
+
+The prestate will typically be generated at:
+
+*   `op-program/bin/prestate.json` (for older versions)
+*   `op-program/bin/prestate.bin.gz` (for intermediate versions)
+*   `op-program/bin/prestate-mt64.bin.gz` (for chains upgraded to Cannon MT64, starting from [upgrade 14](/notices/upgrade-14#whats-included-in-upgrade-14))
+
+<Callout type="info">
+  Post-upgrade 14, chains are expected to use `prestate-mt64.bin.gz` due to the Fault Proof VM contract upgrade to `cannon-mt64`.
+  The older `prestate.bin.gz` will eventually be deprecated but is temporarily retained until all chains complete the upgrade.
+</Callout>
+
+### Ensure sufficient funds for bonds
+
+Bonds are required for both permissioned and permissionless games.
+However, with permissioned games, you typically don't post claims regularly, making bond requirements less noticeable.
+In contrast, the challenger in permissionless games will frequently need to post bonds with each claim it makes.
+Therefore, ensure your challenger has sufficient funds available.
+
+As a general guideline:
+
+*   Maintain a minimum balance of 50 ETH
+*   Have access to a large pool of ETH for potential attack scenarios
+*   Implement monitoring to ensure sufficient funds are always available
+
+### Set up `op-dispute-mon`
+
+Ensure `op-dispute-mon` is properly configured by following these [steps](/operators/chain-operators/tools/chain-monitoring#dispute-mon)
+
+## 2. Deploy and configure smart contracts using OPCM
+
+This section requires privileged actions by the `ProxyAdminOwner` and may involve the `Guardian` role depending on your security setup.
+
+### Understanding ProxyAdmin Owner and Guardian roles
+
+This migration requires actions by privileged roles in your system:
+
+*   The **ProxyAdmin Owner** has the authority to upgrade proxy contracts.
+
+*   The **Guardian** has emergency powers like pausing withdrawals and changing the respected game type.
+
+For detailed information about privileged roles and their security implications, refer to the [privileged roles documentation](/superchain/privileged-roles).
+
+### Adding the PermissionlessDisputeGame to a chain
+
+Given that not all chains will support the `PermissionlessDisputeGame` upon deployment, an
+`OPCM.addGameType()` method will be added which will orchestrate the actions required to add a
+new game type.
+
+This method will:
+
+1.  deploy the `FaultDisputeGame` contract
+2.  setup the `DelayedWethProxy` for the new game
+3.  Reinitialize the `AnchorStateRegistry` to add the new game type.
+
+See a high level implementation from the (spec]\([https://specs.optimism.io/experimental/op-contracts-manager.html#implementation-2](https://specs.optimism.io/experimental/op-contracts-manager.html#implementation-2))
+
+### Set game implementations
+
+Execute the following smart contract changes in a single bundled transaction:
+
+1.  Call `setImplementation` on the `DisputeGameFactoryProxy` to:
+
+    *   Set the implementation for the new permissionless `FaultDisputeGame` (game type `0`)
+    *   Upgrade the permissioned game to the new `PermissionedDisputeGameAddress` (game type `1`) with the updated absolute prestate
+
+2.  Upgrade the `AnchorStateRegistryProxy` (pre-Upgrade 13 only):
+
+    After [upgrade 13](/notices/upgrade-13#whats-included-in-upgrade-13) (FP incident response improvements), this step is *no longer required*, as a single anchor state is shared across all game types. If you have not upgraded, perform the following:
+
+    *   First upgrade the proxy to point to the `StorageSetter` contract and clear the initialized flag.
+    *   Then upgrade back to the `AnchorStateRegistry` implementation
+    *   Call `initialize` with the anchor state for the new game type
+
+<Callout type="info">
+  Ensure a permissioned game has already resolved with the correct root and updated the anchor state to a valid value.
+  Initial deployments at genesis always have an invalid anchor state.
+</Callout>
+
+Post-upgrade 13, the anchor state for permissionless games automatically matches the current anchor state used by permissioned games, since there's only one shared anchor state.
+
+3.  // TODO: Initialize bond amounts for each game type to exactly 0.08 ETH
+
+## 3. Testing off-chain agents
+
+After you've set the permissionless `FaultDisputeContract` implementations on the `DisputeGameFactory` and before you set the respected game type to it; you can test your off-chain services in the cold path.
+
+### Test defending valid proposals
+
+Create a valid proposal using the permissionless game type `0`:
+
+1.  Ensure the proposal is from a block at or before the `safe` head:
+    ```bash
+    cast block --rpc-url <OP_GETH_ENDPOINT> safe
+    ```
+
+2.  Get a valid output root:
+    ```bash
+    cast rpc --rpc-url <OP_NODE_ENDPOINT> optimism_outputAtBlock \
+      $(cast 2h <BLOCK_NUMBER>) | jq -r .outputRoot
+    ```
+
+3.  Create a test game:
+    ```bash
+    ./op-challenger/bin/op-challenger create-game \
+      --l1-eth-rpc=<L1_RPC_ENDPOINT> \
+      --game-factory-address <DISPUTE_GAME_FACTORY_ADDR> \
+      --l2-block-num <BLOCK_NUMBER> \
+      --output-root <OUTPUT_ROOT> \
+      <SIGNER_OPTIONS>
+    ```
+
+4.  Verify:
+    *   `op-challenger` logs a message showing the game is in progress
+    *   `op-challenger` doesn't post a counter claim (as this is a valid proposal)
+    *   `dispute-mon` includes the new game with `status="agree_defender_ahead"`
+
+### Test countering invalid claims
+
+Post an invalid counter claim to the valid proposal created above:
+
+```bash
+./op-challenger/bin/op-challenger move \
+  --l1-eth-rpc <L1_RPC_ENDPOINT> \
+  --game-address <GAME_ADDR> \
+  --attack \
+  --parent-index 0 \
+  --claim 0x0000000000000000000000000000000000000000000000000000000000000000 \
+  <SIGNER_OPTIONS>
+```
+
+Verify that `op-challenger` posts a counter-claim to the invalid claim. You can view claims using:
+
+```bash
+./op-challenger/bin/op-challenger list-claims \
+  --l1-eth-rpc <L1_RPC_ENDPOINT> \
+  --game-address <GAME_ADDR>
+```
+
+There should be 3 claims in the game after this test.
+
+## 4. Switch to permissionless proofs
+
+After completing all previous steps and verifying their successful operation:
+
+1.  Set the `respectedGameType` on the `OptimismPortal` to `CANNON` (game type `0`) using OPCM:
+    ```bash
+    opcm set-respected-game-type \
+      --game-type 0
+    ```
+
+2.  Configure `op-proposer` to create proposals using the permissionless `cannon` game type:
+
+    ```bash
+    # Change from game-type 1 to 0
+    --game-type 0
+    ```
+
+    Or via environment variable:
+
+    ```
+    OP_PROPOSER_GAME_TYPE=0
+    ```
+
+## Next steps
+
+*   [Optimism Fault Proof Documentation](/operators/chain-operators/tools/op-challenger)
+*   [Privileged Roles Documentation](/superchain/privileged-roles)
+*   [L2Beat OP Mainnet Upgrades](https://l2beat.com/scaling/projects/op-mainnet#upgrades-and-governance)
+*   [op-challenger GitHub](https://github.com/ethereum-optimism/optimism/tree/develop/op-challenger)
+*   [op-dispute-mon GitHub](https://github.com/ethereum-optimism/optimism/tree/develop/op-dispute-mon)
+
+## Conclusion
+
+Transitioning to permissionless proofs represents a significant security improvement for your OP Stack chain. This transition decentralizes the validation process, allowing any participant to challenge invalid withdrawal claims rather than relying on a limited set of trusted validators.
+
+By following this guide, you'll be able to safely configure and test your system before making the switch to permissionless proofs. Remember to thoroughly test each service before proceeding to the next step, and ensure that your security monitoring is properly configured to track the health of the system after the transition.

words.txt

@@ -264,7 +264,6 @@ offchain
 opchaina
 opchainb
 OPCM
-opcm
 Openfort
 oplabs
 opnode's