Origins
On November 15, 2018, Bitcoin Cash (BCH) planned a protocol upgrade (v0.18). However, nChain—an Australian company led by Dr. Craig Wright, who claimed to be Satoshi Nakamoto—opposed Bitcoin ABC’s (ABC) roadmap. Instead, nChain advocated for keeping BCH’s protocol simple, avoiding complex restrictions, and announced its own client, Bitcoin SV (SV). Notably, SV omitted replay protection, directly competing with the existing BCH chain.
SV stands for Satoshi’s Vision.
What Is Replay Protection?
Without replay protection, a single transaction can be broadcast and validated on both the ABC and SV chains. To prevent this, transactions should include a unique FORKID to help miners identify the correct chain.
For example, after Bitcoin Cash forked from Bitcoin (BTC), BCH implemented:
SIGHASH_FORKID = 0x40
This ensured transactions were chain-specific (Source 1).
Risks of No Replay Protection:
- Double-Spending: The same transaction could be confirmed on both chains.
- Chain Chaos: Conflicting block heights and inconsistent ledger states.
- Selfish Mining Attacks: Majority hash rate could force chain reorganizations (reorgs), destabilizing transactions.
Why Did SV Skip Replay Protection?
- Strategic Aggression: SV aimed to challenge ABC’s dominance.
- Governance Clash: Hard forks typically require community consensus, but SV bypassed this.
- Node Upgrade Burden: Replay protection would force all nodes to upgrade—a logistical hurdle.
Who’s Affected?
| Stakeholder | Impact |
|---|---|
| BCH Community | Prolonged network instability, miner attrition. |
| Investors | Price volatility; potential gains from forked coins ("free candy"). |
| Exchanges | Must carefully manage ABC/SV splits to avoid accounting errors. |
Exchanges Note: Post-fork snapshots are critical to segregate ABC/SV balances.
Hash Rate Analysis
- BTC’s Shadow: Miners could shift between BTC and BCH, influencing the war.
- Centralization Risks: SV’s concentrated hash rate might push out smaller miners.
How to Protect Your Assets
Method 1: Opcode Isolation
- Use chain-specific opcodes (e.g., ABC supports
OP_CHECKDATASIG; SV supportsOP_INVERT).
Method 2: UTXO "Pollution"
- Mix pre-fork UTXOs with post-fork coins to invalidate transactions on one chain.
Tools:
FAQ
Q: Can I ignore the fork?
A: Yes—hold BCH in a private wallet until the conflict resolves.
Q: Which exchanges support ABC/SV?
A: Major platforms like OKX (see anchor text) typically handle splits.
Q: Will my old BCH wallets work?
A: Only if updated to recognize the new chains.
Conclusion
Initially, ABC held majority support, but SV’s hash rate surge post-November 10 tipped the scales. The outcome remains uncertain, emphasizing the need for cautious asset management.