PolymerProver

Overview

PolymerProver processes proof messages from Polymer’s CrossL2ProverV2 and records proven intents. Unlike other provers, it uses log event proofs rather than direct cross-chain messaging. Contract: contracts/prover/PolymerProver.sol Inheritance: BaseProver, Whitelist, Semver Proof Type: "Polymer"

Polymer uses chain IDs (not custom domain IDs) and validates cross-chain events through cryptographic proofs of event logs.

Constructor

constructor(
    address _portal,
    address _crossL2ProverV2,
    uint256 _maxLogDataSize,
    bytes32[] memory _proverAddresses
)

Initializes the PolymerProver contract.

_portal

address

required

Address of the Portal contract

_crossL2ProverV2

address

required

Address of Polymer’s CrossL2ProverV2 contract

_maxLogDataSize

uint256

required

Maximum allowed size for encodedProofs in IntentFulfilledFromSource event data. Must be between 1 and 32,768 bytes (32 KB).

_proverAddresses

bytes32[]

required

Array of whitelisted prover addresses (as bytes32)

Errors:

ZeroAddress(): CrossL2ProverV2 address is zero
InvalidMaxLogDataSize(): maxLogDataSize is zero or exceeds MAX_LOG_DATA_SIZE_GUARD (32 KB)
ZeroPortal(): Portal address is zero

Location: contracts/prover/PolymerProver.sol:53

State Variables

CROSS_L2_PROVER_V2

ICrossL2ProverV2 public immutable CROSS_L2_PROVER_V2

Address of Polymer’s CrossL2ProverV2 contract used for validating event proofs.

MAX_LOG_DATA_SIZE

uint256 public MAX_LOG_DATA_SIZE

Maximum allowed size for encodedProofs in event data. Set at construction.

PROOF_TYPE

string public constant PROOF_TYPE = "Polymer"

Constant indicating this contract uses Polymer for proving.

PROOF_SELECTOR

bytes32 public constant PROOF_SELECTOR = keccak256("IntentFulfilledFromSource(uint64,bytes)")

Event signature hash for the IntentFulfilledFromSource event.

Constants

uint256 public constant EXPECTED_TOPIC_LENGTH = 64; // 2 topics * 32 bytes each
uint256 public constant MAX_LOG_DATA_SIZE_GUARD = 32 * 1024; // 32 KB

Core Functions

prove

function prove(
    address /* unused */,
    uint64 sourceChainDomainID,
    bytes calldata encodedProofs,
    bytes calldata /* unused */
) external payable

Emits IntentFulfilledFromSource events that can be proven by Polymer.

sourceChainDomainID

uint64

required

Chain ID of the source chain (Polymer uses actual chain IDs, not domain IDs)

encodedProofs

bytes

required

Encoded (intentHash, claimant) pairs. Must not exceed MAX_LOG_DATA_SIZE.

Behavior:

Validates caller is PORTAL
Validates encodedProofs size doesn’t exceed MAX_LOG_DATA_SIZE
Emits IntentFulfilledFromSource(sourceChainDomainID, encodedProofs)

Errors:

OnlyPortal(): Caller is not the Portal contract
MaxDataSizeExceeded(): encodedProofs exceeds MAX_LOG_DATA_SIZE

Access Control: Only callable by PORTAL Note: This function is payable for compatibility but does not use ETH. Location: contracts/prover/PolymerProver.sol:194

validate

function validate(bytes calldata proof) public

Validates a single proof and processes contained intents.

proof

bytes

required

Proof of an IntentFulfilledFromSource event from Polymer’s CrossL2ProverV2

Behavior:

Calls CROSS_L2_PROVER_V2.validateEvent(proof) to verify the event
Validates emitting contract is whitelisted
Validates topics length is 64 bytes (2 topics)
Validates event signature matches PROOF_SELECTOR
Validates source chain ID matches current chain
Validates destination chain ID from proof data
Processes each (intentHash, claimant) pair

Errors:

InvalidEmittingContract(address): Emitting contract not whitelisted
InvalidTopicsLength(): Topics length is not 64 bytes
EmptyProofData(): Data is empty
ArrayLengthMismatch(): Proof data length is invalid
InvalidEventSignature(): Event signature doesn’t match
InvalidSourceChain(): Source chain ID doesn’t match current chain
InvalidDestinationChain(): Destination chain from proof data doesn’t match validateEvent result

Location: contracts/prover/PolymerProver.sol:83

validateBatch

function validateBatch(bytes[] calldata proofs) external

Validates multiple proofs in a batch.

proofs

bytes[]

required

Array of proof data to validate

Behavior: Iterates through each proof and calls validate(proof). Location: contracts/prover/PolymerProver.sol:73

getProofType

function getProofType() external pure override returns (string memory)

Returns: "Polymer"

Internal Functions

processIntent

function processIntent(
    bytes32 intentHash,
    address claimant,
    uint64 destination
) internal

Processes a single intent proof.

intentHash

bytes32

required

Hash of the intent being proven

claimant

address

required

Address that fulfilled the intent and should receive rewards

destination

uint64

required

Destination chain ID for the intent

Behavior:

If intent already proven, emits IntentAlreadyProven and returns
Otherwise, stores proof data and emits IntentProven

Location: contracts/prover/PolymerProver.sol:158

Events

IntentFulfilledFromSource

event IntentFulfilledFromSource(
    uint64 indexed source,
    bytes encodedProofs
)

Emitted on the destination chain when prove() is called. This event is later proven on the source chain using Polymer’s proof system.

source

uint64

required

Chain ID of the source chain (where intent was created)

encodedProofs

bytes

required

Encoded (intentHash, claimant) pairs

Proof Validation Flow

Polymer uses a unique two-step flow:

Destination Chain: Call prove() on PolymerProver to emit IntentFulfilledFromSource event
Source Chain: Generate event proof using Polymer’s infrastructure
Source Chain: Call validate() or validateBatch() with the proof to process intents

Event Data Format

The IntentFulfilledFromSource event data is ABI-encoded bytes containing:

[chainId (8 bytes)][intentHash1 (32 bytes)][claimant1 (32 bytes)][intentHash2]...

Validation Steps

CrossL2ProverV2 Validation:
- Polymer’s CrossL2ProverV2 cryptographically verifies the event occurred on destination chain
- Returns: destinationChainId, emittingContract, topics, data
Authorization Check:
- Validates emittingContract is whitelisted (must be trusted PolymerProver instance)
Event Signature Validation:
- Verifies topics[0] matches PROOF_SELECTOR
- Verifies topics[1] (source chain ID) matches current chain
Data Validation:
- Decodes ABI-encoded bytes from event data
- Extracts chain ID from first 8 bytes
- Verifies chain ID matches destinationChainId from CrossL2ProverV2
Intent Processing:
- Iterates through (intentHash, claimant) pairs
- Skips invalid EVM addresses
- Stores proof data or emits IntentAlreadyProven

Usage Example

On Destination Chain (Intent Fulfillment)

// After fulfilling intent on destination chain, emit proof event
portal.prove(
    address(polymerProver),
    sourceChainId, // Actual chain ID, not domain ID
    encodedProofs, // (intentHash, claimant) pairs
    "" // data parameter unused
);

// This emits IntentFulfilledFromSource(sourceChainId, encodedProofs)

On Source Chain (Proof Validation)

// Generate proof using Polymer's infrastructure (off-chain)
bytes memory proof = generatePolymerProof(...);

// Validate proof on source chain
polymerProver.validate(proof);

// Or validate multiple proofs at once
bytes[] memory proofs = [proof1, proof2, proof3];
polymerProver.validateBatch(proofs);

Domain ID vs Chain ID

Polymer uses actual chain IDs, not custom domain IDs. The sourceChainDomainID parameter in prove() should be the actual chain ID of the source chain.Examples:

Ethereum Mainnet: 1
Optimism: 10
Arbitrum: 42161
Base: 8453

Security Considerations

Whitelist Management

Only whitelisted prover addresses can emit valid IntentFulfilledFromSource events. This prevents unauthorized proof submissions.

Max Log Data Size

The MAX_LOG_DATA_SIZE limit prevents:

Excessive gas costs during event emission
Potential DoS attacks via large event logs
Storage bloat from oversized proofs

Address Validation

The validate() function skips non-EVM addresses (where upper 96 bits are non-zero), ensuring compatibility with EVM-based reward claims.

Core Contracts

Provers

ERC-7683

Types & Interfaces

Utilities

Overview

Constructor

State Variables

CROSS_L2_PROVER_V2

MAX_LOG_DATA_SIZE

PROOF_TYPE

PROOF_SELECTOR

Constants

Core Functions

prove

validate

validateBatch

getProofType

Internal Functions

processIntent

Events

IntentFulfilledFromSource

Proof Validation Flow

Event Data Format

Validation Steps

Usage Example

On Destination Chain (Intent Fulfillment)

On Source Chain (Proof Validation)

Domain ID vs Chain ID

Security Considerations

Whitelist Management

Max Log Data Size

Address Validation

Build docs developers (and LLMs) love

Core Contracts

Provers

ERC-7683

Types & Interfaces

Utilities

​Overview

​Constructor

​State Variables

​CROSS_L2_PROVER_V2

​MAX_LOG_DATA_SIZE

​PROOF_TYPE

​PROOF_SELECTOR

​Constants

​Core Functions

​prove

​validate

​validateBatch

​getProofType

​Internal Functions

​processIntent

​Events

​IntentFulfilledFromSource

​Proof Validation Flow

​Event Data Format

​Validation Steps

​Usage Example

​On Destination Chain (Intent Fulfillment)

​On Source Chain (Proof Validation)

​Domain ID vs Chain ID

​Security Considerations

​Whitelist Management

​Max Log Data Size

​Address Validation

Build docs developers (and LLMs) love

Overview

Constructor

State Variables

CROSS_L2_PROVER_V2

MAX_LOG_DATA_SIZE

PROOF_TYPE

PROOF_SELECTOR

Constants

Core Functions

prove

validate

validateBatch

getProofType

Internal Functions

processIntent

Events

IntentFulfilledFromSource

Proof Validation Flow

Event Data Format

Validation Steps

Usage Example

On Destination Chain (Intent Fulfillment)

On Source Chain (Proof Validation)

Domain ID vs Chain ID

Security Considerations

Whitelist Management

Max Log Data Size

Address Validation