Wiki / Category
Category: Concepts
17 articles · Mechanisms: drivechains, replay protection, activation methods.
Claim-based airdrops
Coins that were not chain splits but let Bitcoin holders claim new tokens: CLAMs, Byteball, Stellar, Bitcore, BTCH, MimbleWimbleCoin and HEX.
Drivechains (BIP-300/301)
Sidechains whose two-way peg is secured by miners (BIP-300) with blind merged mining (BIP-301).
Snapshot forks vs chain splits
Why some “forks” share Bitcoin's history and others only copy its balances, and why it matters for claiming coins.
The timewarp bug
A flaw in Bitcoin's difficulty adjustment that lets a hashrate majority lower difficulty by faking block timestamps; BIP-54 proposes the fix.
Hard fork vs soft fork
The two ways to change Bitcoin's rules: soft forks tighten them and stay backward-compatible; hard forks loosen them and need everyone to upgrade.
Merged mining
Reusing the same proof of work on a parent chain and one or more auxiliary chains, pioneered by Namecoin with Bitcoin as the parent.
BIP9 (version bits)
The 2015 mechanism that lets miners signal for several soft forks in parallel using bits of the block version, with a 95% threshold and a timeout.
Replay protection
Making a transaction valid on only one side of a chain split, so that spending coins on one chain cannot be replayed on the other.
Segregated Witness
The 2017 soft fork that moved signatures out of the legacy block, fixed malleability and became the centre of the block size war.
Source note: the 2019 fork list (johnsmithx)
The Bitcointalk list of 43 reviewed Bitcoin forks that this wiki cites as bth-review: who wrote it, how it tested forks, and its limits.
CTOR (canonical transaction ordering)
Bitcoin Cash's November 2018 rule that transactions in a block, after the coinbase, be sorted by txid — one of the two changes behind the BCH/BSV split.
OP_CHECKDATASIG
A Bitcoin Cash opcode, enabled in November 2018, that checks a signature over arbitrary data; it enabled oracles and early covenants and was one cause of the BSV split.
Great Consensus Cleanup (BIP-54)
A soft fork bundling fixes for the timewarp bug, slow-to-validate blocks, 64-byte transactions and duplicate coinbases; first drafted in 2019 and specified as BIP-54 in 2025.
Speedy Trial
The 2021 version-bits variant used to activate Taproot: a short miner-signalling window at 90% with a delayed minimum activation height.
Avalanche (consensus)
A family of leaderless, metastable voting protocols that eCash layers on top of Nakamoto consensus to finalise blocks and, since 2025, transactions.
Ordinals and inscriptions
Casey Rodarmor's numbering scheme for satoshis and the inscriptions built on it, which put arbitrary data in Taproot witnesses from 2023 and set off the data-carrier dispute.
CashTokens
Native fungible and non-fungible tokens on Bitcoin Cash, specified in CHIP-2022-02 and activated in the 15 May 2023 network upgrade.