feat: implement challenger proving fault with zkVM proof (#386)

* feat(contracts): revive `getChallenge` method of `Colosseum`

* feat(validator): prove fault with witness generator, zkVM prover

* feat: verify zkVM program verification key

* fix: launch kroma-challenger in devnet

* chore(contracts): update bindings and snapshot

* feat: use rpc client for proof fetcher, witness generator

kroma-devnet/devnet/__init__.py

@@ -249,7 +249,6 @@ def devnet_deploy(paths):
             '--outfile.rollup', paths.rollup_config_path
         ], cwd=paths.op_node_dir)
 
-    rollup_config = read_json(paths.rollup_config_path)
     addresses = read_json(paths.addresses_json_path)
 
     # Start the L2.
@@ -266,8 +265,6 @@ def devnet_deploy(paths):
     # Print out the addresses being used for easier debugging.
     l2_output_oracle = addresses['L2OutputOracleProxy']
     log.info(f'Using L2OutputOracle {l2_output_oracle}')
-    batch_inbox_address = rollup_config['batch_inbox_address']
-    log.info(f'Using batch inbox {batch_inbox_address}')
     colosseum = addresses['ColosseumProxy']
     log.info(f'Using Colosseum {colosseum}')
     validator_pool = addresses['ValidatorPoolProxy']
@@ -278,14 +275,13 @@ def devnet_deploy(paths):
     log.info(f'Using AssetManager {asset_manager}')
 
     log.info('Bringing up `kroma-node`, `kroma-batcher` and `kroma-validator`.')
-    run_command(['docker', 'compose', 'up', '-d', 'kroma-node', 'kroma-batcher', 'kroma-validator'], cwd=paths.ops_bedrock_dir, env={
+    run_command(['docker', 'compose', 'up', '-d', 'kroma-node', 'kroma-batcher', 'kroma-validator', 'kroma-challenger'], cwd=paths.ops_bedrock_dir, env={
         'PWD': paths.ops_bedrock_dir,
         'L2OO_ADDRESS': l2_output_oracle,
         'COLOSSEUM_ADDRESS': colosseum,
         'VALPOOL_ADDRESS': validator_pool,
         'VALMGR_ADDRESS': validator_manager,
         'ASSETMANAGER_ADDRESS': asset_manager,
-        'SEQUENCER_BATCH_INBOX_ADDRESS': batch_inbox_address
     })
 
     log.info("Deposit ETH into ValidatorPool contract to be a validator...")

kroma-validator/challenge/proof_fetcher.go

@@ -0,0 +1,114 @@
+package challenge
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"github.com/ethereum-optimism/optimism/op-service/client"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+type ZkEVMProofFetcher struct {
+	rpc client.RPC
+}
+
+type ZkEVMProveResponse struct {
+	FinalPair []byte `json:"final_pair"`
+	Proof     []byte `json:"proof"`
+}
+
+type ProofAndPair struct {
+	Proof []*big.Int
+	Pair  []*big.Int
+}
+
+func NewZkEVMProofFetcher(rpc client.RPC) *ZkEVMProofFetcher {
+	return &ZkEVMProofFetcher{rpc}
+}
+
+func (z *ZkEVMProofFetcher) FetchProofAndPair(ctx context.Context, trace string) (*ProofAndPair, error) {
+	var output *ZkEVMProveResponse
+	err := z.rpc.CallContext(ctx, &output, "prove", trace)
+	if err != nil {
+		return nil, fmt.Errorf("failed to request prove: %w", err)
+	}
+
+	proofAndPair := &ProofAndPair{
+		Proof: decode(output.Proof),
+		Pair:  decode(output.FinalPair),
+	}
+
+	return proofAndPair, nil
+}
+
+func decode(data []byte) []*big.Int {
+	result := make([]*big.Int, len(data)/32)
+
+	for i := 0; i < len(data)/32; i++ {
+		// The best is data is given in Big Endian.
+		for j := 0; j < 16; j++ {
+			data[i*32+j], data[i*32+31-j] = data[i*32+31-j], data[i*32+j]
+		}
+		result[i] = new(big.Int).SetBytes(data[i*32 : (i+1)*32])
+	}
+
+	return result
+}
+
+type ZkVMProofFetcher struct {
+	rpc client.RPC
+}
+
+type HexBytes []byte
+
+type ZkVMProofResponse struct {
+	RequestStatus RequestStatusType `json:"request_status"`
+	VKeyHash      common.Hash       `json:"vkey_hash"`
+	RequestID     string            `json:"request_id"`
+	PublicValues  HexBytes          `json:"public_values"`
+	Proof         HexBytes          `json:"proof"`
+}
+
+func NewZkVMProofFetcher(rpc client.RPC) *ZkVMProofFetcher {
+	return &ZkVMProofFetcher{rpc}
+}
+
+func (z *ZkVMProofFetcher) Spec(ctx context.Context) (*SpecResponse, error) {
+	var output *SpecResponse
+	err := z.rpc.CallContext(ctx, &output, "spec")
+	return output, err
+}
+
+func (z *ZkVMProofFetcher) RequestProve(ctx context.Context, blockHash string, l1Head string, witness string) (*RequestStatusType, error) {
+	var output *RequestStatusType
+	err := z.rpc.CallContext(ctx, &output, "requestProve", blockHash, l1Head, witness)
+	return output, err
+}
+
+func (z *ZkVMProofFetcher) GetProof(ctx context.Context, blockHash string, l1Head string) (*ZkVMProofResponse, error) {
+	var output *ZkVMProofResponse
+	err := z.rpc.CallContext(ctx, &output, "getProof", blockHash, l1Head)
+	return output, err
+}
+
+// UnmarshalJSON handles the conversion from a hex string to a byte array.
+func (h *HexBytes) UnmarshalJSON(data []byte) error {
+	// Remove quotes around the hex string
+	str := string(data)
+	if len(str) >= 2 && str[0] == '"' && str[len(str)-1] == '"' {
+		str = str[1 : len(str)-1]
+	}
+
+	// Decode the hex string to byte array
+	str = strings.TrimPrefix(str, "0x")
+	decoded, err := hex.DecodeString(str)
+	if err != nil {
+		return err
+	}
+
+	*h = decoded
+	return nil
+}

kroma-validator/challenge/witness_generator.go

@@ -0,0 +1,55 @@
+package challenge
+
+import (
+	"context"
+
+	"github.com/ethereum-optimism/optimism/op-service/client"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+const (
+	RequestNone       RequestStatusType = "None"
+	RequestProcessing RequestStatusType = "Processing"
+	RequestCompleted  RequestStatusType = "Completed"
+	RequestFailed     RequestStatusType = "Failed"
+)
+
+type WitnessGenerator struct {
+	rpc client.RPC
+}
+
+type SpecResponse struct {
+	Version    string      `json:"version"`
+	SP1Version string      `json:"sp1_version"`
+	VKeyHash   common.Hash `json:"vkey_hash"`
+}
+
+type RequestStatusType string
+
+type WitnessResponse struct {
+	RequestStatus RequestStatusType `json:"status"`
+	VKeyHash      common.Hash       `json:"vkey_hash"`
+	Witness       string            `json:"witness"`
+}
+
+func NewWitnessGenerator(rpc client.RPC) *WitnessGenerator {
+	return &WitnessGenerator{rpc}
+}
+
+func (w *WitnessGenerator) Spec(ctx context.Context) (*SpecResponse, error) {
+	var output *SpecResponse
+	err := w.rpc.CallContext(ctx, &output, "spec")
+	return output, err
+}
+
+func (w *WitnessGenerator) RequestWitness(ctx context.Context, blockHash string, l1Head string) (*RequestStatusType, error) {
+	var output *RequestStatusType
+	err := w.rpc.CallContext(ctx, &output, "requestWitness", blockHash, l1Head)
+	return output, err
+}
+
+func (w *WitnessGenerator) GetWitness(ctx context.Context, blockHash string, l1Head string) (*WitnessResponse, error) {
+	var output *WitnessResponse
+	err := w.rpc.CallContext(ctx, &output, "getWitness", blockHash, l1Head)
+	return output, err
+}