Replay Protection
security · fork
Consensus or wallet techniques that stop or reduce unintended reuse of the same signed transaction across split chains.
Strong replay protection changes consensus validation—often signature hashing or transaction rules—so a transaction signed for one side of a chain split is invalid on the other. Protection can be two-way or only protect transactions created under one chain's new rules.
When consensus-level protection is absent, wallets can split coins by first creating outputs whose histories differ across the chains and then spending them separately. Different address prefixes can reduce user confusion but do not by themselves prevent replay when the underlying script and signature remain valid on both chains.
Related terms
Replay Attack
→When a valid transaction from one chain is maliciously or accidentally broadcast and accepted on another chain after a fork.
security · fork
Chain Split
→A divergence in which nodes accept competing block histories; it may resolve by reorganization or persist as separate networks.
blockchain · governance
Fork
→A fork is a blockchain divergence caused by competing blocks, software changes, or incompatible consensus rules.
blockchain · event