Payment Channels и L2

Зачем L2 если TON уже быстрый?

TON обрабатывает ~100K TPS через sharding — зачем L2? Для micropayments: даже $0.007 per tx слишком много для тысяч мелких платежей (streaming payments, gaming in-app purchases, IoT micro-transactions).

Payment Channels: концепция

Payment channel — два участника открывают off-chain канал, обмениваются signed states, и записывают только final state on-chain:

Payment Channel Flow:

1. OPEN: Alice и Bob депонируют по 50 TON в channel contract
   On-chain: 1 tx (create contract + deposits)

2. OFF-CHAIN UPDATES (бесплатно, мгновенно):
   State 1: Alice=50, Bob=50 (initial)
   State 2: Alice=45, Bob=55 (Alice paid Bob 5)
   State 3: Alice=40, Bob=60 (Alice paid Bob 5 more)
   ... thousands of updates, 0 on-chain tx

3. CLOSE: записать final state (Alice=40, Bob=60)
   On-chain: 1 tx (close contract + distribute)

Total on-chain: 2 tx for unlimited off-chain payments!

Cooperative vs Uncooperative Close

Cooperative Close:
  Оба согласны с final state → 1 tx → instant

Uncooperative Close:
  Один не согласен → challenge period
  1. Alice submits her latest signed state
  2. Challenge period (e.g., 24 hours)
  3. Bob can submit newer signed state during challenge
  4. After challenge → latest state wins → distribute

TON Payment Network (2025 Roadmap)

TON Foundation разрабатывает Layer 2 Payment Network:

• Instant transfers с минимальными fees
• Network of payment channels (Lightning Network style)
• Smooth asset exchanges
• Планируется в рамках TON 2025 roadmap (Accelerator upgrade)

Design Implications

When to use Payment Channels

Security Model

Security:
  - Funds locked in smart contract (not with counterparty)
  - Latest signed state = proof of balance
  - Challenge mechanism prevents fraud
  - Timeout: if counterparty disappears → unilateral close after period