Home/Blockchain/Fraud Proofs Visualized/Challenge System

⚠️ Challenge System: 7-Day Dispute Window

Understand the challenge period and how verifiers dispute invalid batches

Understand how optimistic rollups stay secure

Your Progress

0 / 5 completed
1
2
3
4
5

⏱️ Challenge Period Timeline

The challenge period is a critical window where validators can dispute invalid state transitions. Understanding this timeline is essential for optimistic rollup security.

🎮 Interactive Challenge Timeline

Experience a 7-day challenge period in fast-forward. Watch the timeline progress and decide when to submit your fraud proof challenge!

📤

Batch Submission

Sequencer posts state root to L1

Day
0/7
Timeline Progress0%
Day
0
Day
1
Day
2
Day
3
Day
4
Day
5
Day
6
Day
7

📋 Challenge System Phases

1️⃣

Batch Submission (Day 0)

Sequencer posts a state root to L1 along with a bond. The 7-day challenge window begins.

2️⃣

Monitoring Phase (Days 1-7)

Validators re-execute transactions locally to verify state transitions. If fraud is detected, they prepare a fraud proof.

3️⃣

Challenge Submission

If fraud is found, validator submits a fraud proof to L1. This initiates an on-chain dispute resolution process.

4️⃣

Resolution (Immediate or Day 7)

If challenged, L1 verifies the fraud proof. If proven, sequencer loses bond. If no challenges by Day 7, batch is finalized.

⚡ Fast Path (No Challenges)

  • •Batch submitted with state root + bond
  • •7-day challenge window passes quietly
  • •No fraud proofs submitted
  • •Batch finalized, withdrawals processed
  • •Sequencer bond returned

⚔️ Challenge Path (Fraud Detected)

  • •Validator detects invalid state transition
  • •Fraud proof submitted to L1 (anytime before Day 7)
  • •L1 contract verifies proof on-chain
  • •If valid: Sequencer slashed, state reverted
  • •Validator earns reward from sequencer bond

💡 Why 7 Days?

The 7-day challenge period is a security-UX tradeoff. It must be long enough for validators to:

  • •Download and verify potentially thousands of transactions
  • •Re-execute state transitions locally
  • •Construct fraud proofs if needed
  • •Submit proof to L1 (accounting for network congestion)

Some rollups are exploring shorter periods (1-3 days) with better tooling, but 7 days is the industry standard for maximum security.

← Introduction