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bsc-api-list.md: update fast finality api doc #653

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25 changes: 12 additions & 13 deletions docs/bnb-smart-chain/developers/json_rpc/bsc-api-list.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,13 +7,13 @@ Finality is a crucial aspect of blockchain security, ensuring that once a block

### Probabilistic Finality and Economic Finality

BNB Smart Chain (BSC) implements a dual-layer finality mechanism combining **Economic Finality** and **Probabilistic Finality** to ensure transaction security and network efficiency.
BNB Smart Chain (BSC) implements a dual-layer finality mechanism combining Economic Finality and Probabilistic Finality to ensure transaction security and network efficiency.

#### Economic Finality (Fast Finality)

The **Fast Finality** feature, introduced through **[BEP-126](https://github.com/bnb-chain/BEPs/blob/master/BEPs/BEP126.md)**, enables Economic Finality using a slashing mechanism similar to Casper FFG and Tendermint. Key characteristics:
The Fast Finality feature, introduced through **[BEP-126](https://github.com/bnb-chain/BEPs/blob/master/BEPs/BEP126.md)**, enables Economic Finality using a slashing mechanism similar to Casper FFG and Tendermint. Key characteristics:

- **Block n achieves economic finality by block n+2**
- Block n achieves economic finality by block n+2
- Transaction finality time: **~3.75 seconds** (with 1.5 seconds block time)
- Economic penalties make block reversal extremely expensive
- Validators violating voting rules forfeit part of their staked assets
Expand All @@ -22,19 +22,18 @@ This significantly improves user experience through faster and more reliable tra

#### Probabilistic Finality (Fallback Mechanism)

When Fast Finality is unavailable, BSC falls back to **Probabilistic Finality**. Security increases as more blocks are added - the deeper a block is buried, the lower the probability of reversal.
When Fast Finality is unavailable, BSC falls back to Probabilistic Finality. Security increases as more blocks are added - the deeper a block is buried, the lower the probability of reversal.

**Network Parameters:**
- **TurnLength**: 8 (consecutive blocks per validator)
- **ValidatorSize**: 21 (total active validators)
- **Block Time**: ~1.5 seconds
Network Parameters:

**Finality Requirements:**
- **Majority (>1/2) validator confirmations**: 88 blocks (11 × 8) ≈ **132 seconds**
- **Supermajority (>2/3) validator confirmations**: 120 blocks (15 × 8) ≈ **180 seconds**
- TurnLength: 8 (consecutive blocks per validator)
- ValidatorSize: 21 (total active validators)
- Block Time: ~1.5 seconds

**Formula**: `Required Blocks = n × TurnLength`
- Where **n** = 11 (majority) or 15 (supermajority consensus)
Finality Requirements:

- Majority (>1/2) validator confirmations: 88 blocks (11 × 8) ≈ 132 seconds
- Supermajority (>2/3) validator confirmations: 120 blocks (15 × 8) ≈ 180 seconds

This dual-layer approach ensures network security and finality guarantees even when Fast Finality encounters issues.

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