Crypto Cho Người Mới / Mô phỏng / OR Fraud Proof
Simulator Optimistic Rollup Fraud Proof + Bridge Decision
Optimistic rollup assume state họ correct unless ai prove otherwise. Proof window: 7 ngày. Đây sao withdrawing từ Arbitrum/Optimism/Base về Ethereum L1 take week via native bridge. Fast 3rd-party bridge (Across, Hop, Orbiter) provide instant withdrawal cho fee. Simulator này quote both option, chạy fraud proof game mechanic (~25 bisection round × 24h each), và recommend bridge nào dùng dựa transfer amount.
Bridge từ L2 về L1
Bridge quote
Total fee
$0.00
Fee as % transfer: 0.000%
Estimated time
168 hrs
Bridge risk class: none
Native vs Fast bridge decision
Native fee
$0.00
Native time: 168 hrs
Cheapest fast bridge: orbiter
$25.00
Fast bridge time: 3 min
Extra cost per hour saved (đi fast)
$0.1489/hr
Dùng native bridge (7-day delay OK, save fee)
Interactive Fraud Proof Game
Bisection round needed
24
Gas cost per round
$31.50
Total gas cost (entire game)
$756.00
Bond locked during game
$10.50k
Total time (mỗi round ~24h)
24.0 days
Winner payoff (loser bond)
+$10.50k
Sao optimistic rollup tồn tại và sao 7 ngày
Ethereum L1 alone do được ~15 TPS. Để scale, rollup process transaction OFF-CHAIN, rồi post just STATE ROOT + transaction data back về L1. Compress thousands of L2 tx thành one L1 tx. Sao 'optimistic'? Vì L1 không verify mỗi L2 tx individually — ASSUME posted state correct, và only check nếu challenged. 7-day window là time L1 wait cho fraud challenge. Sau 7 ngày without challenge, state FINAL. Sao 7 ngày specifically? Long enough that: (a) Honest validator detect được fraud even dưới DoS attack. (b) Interactive bisection proof complete được (25 round × 24h each). (c) Network upgrade không interrupt protection.
Fast bridge — work sao và cost gì
Across, Hop, Orbiter, và others là 'fast bridge.' Observe L2 withdrawal request bạn, rồi immediately send bạn L1 fund từ own liquidity họ. Get reimbursed bởi L2 protocol sau 7-day window expire. Fee họ charge (0.05-0.30%) cover: (1) Cost of capital họ (locked liquidity). (2) Bridge security audit họ + smart contract risk. (3) Gas cost họ. Cho đa số user, fast bridge là right choice — bạn pay 0.05-0.30% save 7 ngày. Cho very large transfer, native bridge worth it (no fee). Cho small transfer, fixed component fast bridge fee dominate.
Fraud proof game — interactive bisection protocol
Nếu validator detect fraud trong posted L2 state, họ initiate fraud proof game. Mechanic: asserter say state X correct. Challenger disagree. Họ bisect — asserter say intermediate state Y correct, challenger disagree. Bisect again. Sau log2(N) round where N = total L2 instruction trong dispute, họ narrow down về SINGLE CPU instruction. L1 then execute one instruction đó và determine ai right. Cho ~10M L2 instruction per block, this ~24 round. Mỗi round ~24 giờ game time (parties cần compute proof). Total game time: 25-30 ngày cho major fraud. Nhưng: 7-day challenge window start game; once started, rest take longer được (và L2 stay paused until resolved).
Sao ZK rollup không có 7-day delay này
ZK rollup (zkSync, Starknet, Scroll, Polygon zkEVM) post PROOF state transition họ correct. Verification mathematical — L1 không phải wait cho challenge window vì proof itself guarantee correctness. ZK rollup withdrawal: typically 0-1 giờ. Trade-off: ZK proving computationally intensive ($1000s+ per batch trong 2023, dropping về $100s trong 2024 với hardware advance). Optimistic rollup không có proving cost này. Nên in practice: ZK = expensive proof, fast withdrawal. Optimistic = cheap proof, slow native withdrawal (fast 3rd-party bridge fill UX gap). Both approach dominate different segment market.
Câu hỏi thường gặp
+Fraud proof đã triggered trên real optimistic rollup chưa?
As của 2024, no successful fraud detected trên Arbitrum, Optimism, hoặc Base. 7-day window expired hàng thousands lần without incident. Partly good design (rollup code well-audited), partly small number of validator currently capable submit fraud proof (đa số rollup có vài permissioned validator). True permissionless fraud proof being rolled out — Arbitrum BoLD (2024) open fraud proof cho anyone. Mechanism work trong theory; trong practice, security come từ threat plus existing honest-validator assumption.
+Fast bridge có safe không?
Mostly yes, với caveat. Across generally considered safest — dùng UMA optimistic oracle cho dispute resolution và đã battle-tested. Hop, Orbiter, others cũng generally safe nhưng có occasional issue. Main risk: bridge smart contract bug hoặc exploit, có thể lock hoặc lose user fund. Always check recent bridge security incident trước use. Cho large amount ($100k+), vài user prefer native bridge despite 7-day wait — avoid bridge contract risk.
+Còn Arbitrum One vs Arbitrum Nova vs Orbit chain?
Different product với different security model. Arbitrum One = main optimistic rollup, full L1 security, 7-day withdrawal. Arbitrum Nova = AnyTrust chain — dùng Data Availability Committee thay vì post mọi data về L1, much cheaper nhưng slightly weaker security (depend on DAC trust). Withdrawal từ Nova: still ~7 ngày through native bridge. Orbit chain = Arbitrum framework build custom L3 trên Arbitrum One — có own security model depending configuration. Always check trước bridge.
+Tôi check sao fraud proof window đã expired chưa?
Trên Arbitrum: go bridge.arbitrum.io, view withdrawal bạn. Show L1 inclusion time và remaining wait period. Trên Optimism: app.optimism.io/bridge với same info. Trên Base: bridge.base.org. Sau 7 ngày expire, bạn click 'Claim' trên L1 và pay L1 gas fee finalize withdrawal. Native bridge sẽ refund full amount bạn; fast bridge already pre-paid bạn. Always wait full window pass trước claim hoặc bạn waste gas.
+Có 'emergency withdrawal' nếu rollup get stuck không?
Mọi major optimistic rollup có FORCE INCLUSION mechanism — nếu rollup operator pause hoặc go offline, user still submit được transaction through L1 contract force inclusion. Include withdrawal. Clunky (more expensive, multi-step) nhưng ensure user always exit được. 'Escape hatch' này là part of sao rollup considered safer hơn pure sidechain (Polygon PoS, BSC) — even nếu operator hostile, user recover được fund. Escape hatch rarely used (rollup đã reliable), nhưng có đó như backstop.