CDK add pp intro doc

Author: EmpieichO

docs/cdk/releases/pp-intro-components.md

@@ -0,0 +1,64 @@
+<!-- # Pessimistic proofs (PP) -->
+
+Developers can use CDK to configure custom ZK-rollups by choosing which components should run the Polygon zkEVM protocol. We refer to these chains as CDK sovereign chains.
+
+Developers can, for instance, configure their chains to use provers that are outside the Polygon zkEVM stack.
+
+Specifically, instead of deploying a Polygon zkEVM prover, developers can configure their CDK sovereign chains to utilize Succinct's SP1 prover.
+
+Since CDK sovereign chains are designed to easily connect to the AggLayer, they use a type of ZK-proof called a _pessimistic proof_ to reach finality of transactions.
+
+## What is a pessimistic proof?
+
+A *pessimistic proof* (PP) is a zero-knowledge proof attesting to the fact that a chain's bridge transitions were correctly executed and that all withdrawals are collateralized.
+
+Therefore, pessimistic proofs enable CDK-built chains that interoperate via the [unified bridge](../../zkEVM/architecture/unified-LxLy/index.md) to achieve trustless cross-chain security. 
+
+Pessimistic proofs allow CDK sovereign chains connected to the [AggLayer](../../agglayer/overview.md) interoperate securely
+
+We henceforth refer to CDK sovereign chains as CDK PP chains.
+
+## CDK PP stack
+
+Next, we detail the architectural components of the CDK PP chains.
+
+The table below lists the components of a CDK PP chain and where you can find them.
+
+| Component                | CDK PP stack                                                 | Notes                                                        |
+| ------------------------ | ------------------------------------------------------------ | ------------------------------------------------------------ |
+| Node = RPC and sequencer | [cdk-erigon](https://github.com/0xPolygonHermez/cdk-erigon)  | Customizable, commonly:<br/>\- Sequencer = 1 node<br/>\- RPC = multiple nodes |
+| Contracts                | <a href=https://github.com/0xPolygonHermez/zkevm-contracts>zkevm-contracts</a> |                                                              |
+| CLI                      | [cdk](https://github.com/0xPolygon/cdk)                      | Included in [CDK](https://github.com/0xPolygon/cdk) repo     |
+| AggSender                | <a href=https://github.com/0xPolygon/cdk>cdk</a>             | Included in [CDK](https://github.com/0xPolygon/cdk) repo     |
+| Tx pool manager          | <a href=https://github.com/0xPolygon/zkevm-pool-manager>  zkevm-pool-manager</a> |                                                              |
+
+## Component descriptions
+
+Here are brief descriptions for each CDK FEP component.
+
+- CDK Erigon node, a fork of [erigon](https://github.com/ledgerwatch/erigon), that manages the following:
+  - Multiple RPC nodes that provide common APIs for sending transactions.
+  - Sequencer for executing transactions, and creating blocks and batches.
+- DAC: The Data Availability Committee, specifically for validium mode, is a set of *trusted actors* who keep custody of all transaction data, including monitoring and validating hash values the sequencer sender proposes to publish on L1.
+- Contracts: Various smart contracts deployed on L1 for the full implementation and complete functionality of the Polygon zkEVM protocol:
+  - `PolygonRollupManager`
+  - `PolygonZkEVMBridgeV2`
+  - `PolygonZkEVMGlobalExitRootV2`
+  - `FflonkVerifier`
+  - `PolygonZkEVMDeployer`
+  - `PolygonZkEVMTimelock`
+- CLI tool: A single command line interface tool for abstracting away the complexity of deploying or configuring CDK components.
+- AggSender is the CDK PP component that accumulates all necessary info in order to generate certificates, which are sent to the SP1 prover via the JSON-RPC API  for the generation of pessimistic proofs.
+- Transaction pool manager: For storing transactions submitted by users.
+
+## AggLayer-side components
+
+- Succinct's SP1 prover: A simplified cryptographic tool designed to take Rust-written inputs in order to generate ZK-proofs.
+
+  Unlike in the CDK FEP chain, the prover in a CDK PP chain is not directly connected to the chain. It in fact resides in the AggLayer.
+
+- JSON-RPC API: A component provided by the AggLayer to interface between the CDK PP chain and the SP1 prover.
+
+  In reality, the AggSender sends certificates to the JSON-RPC API, which in turn requests the SP1 prover to generate ZK-proofs. On receipt of the ZK-proofs, it sends the ZK-proofs to L1.
+
+  See the high level view of the CDK PP chain architecture [here](../architecture/high-level-views.md)

mkdocs.yml

@@ -55,6 +55,7 @@ nav:
       - Overview: cdk/overview.md
       - Releases:
         - Full execution proofs (FEP): cdk/releases/stack-components.md
+        - Pessimistic proofs (PP): cdk/releases/pp-intro-components.md
       - Get started:
         - Local deployment guide: cdk/getting-started/local-deployment.md
         - CLI tool: cdk/getting-started/cli-tool.md