Control profile
- Transaction ordering
- Permissionless proof-of-work miners choose and order the valid transactions in each block; full nodes independently enforce the consensus rules.
- Escape hatch
- n/a — native settlement layer with no bridge or sequencer exit dependency
- Upgrade authority
- No administrator or upgrade key. Rule changes depend on software adoption by miners, economic actors, and independently operated full nodes.
- Liveness record
- Mainnet block production is continuous and finality is probabilistic rather than instant. Temporary forks resolve by accumulated proof of work, so deep reorgs and sustained control of a majority of hashpower are the observable safety events rather than a named operator halt.
Ketju assessment
APPROVED as a settlement layer. Bitcoin has the cleanest control model in this expansion batch: permissionless block production, independently enforced rules, no bridge beneath the native asset, and no key that can rewrite balances or compel a protocol upgrade. Mining pools remain operational coordination points and probabilistic finality demands a confirmation policy, but neither creates the unilateral administrative control that this chain grade is designed to detect.
Observable review triggers
- A single coordinated mining entity sustaining more than 50% of observed hashpower
- A reorganisation deeper than six blocks
- A consensus split that leaves economically significant incompatible chains for more than 24 hours
These triggers make the judgment monitorable. They are not predictions; each identifies a fact that would revoke or force review of the current assessment.
Advisor implementation questions
- Does the client’s thesis require censorship resistance, or primarily low-cost settlement?
- Can the client exit without cooperation from the normal transaction-ordering party?
- Who can upgrade bridges or contracts, and what delay applies?
- Does the asset introduce an issuer weaker than the chain grade?
- What evidence will show a halt, censorship event, or governance change?
Research sources
- Bitcoin Developer Guide — Block Chain — full-node validation, proof-of-work chain selection, probabilistic finality
- Bitcoin Developer Guide — Mining — permissionless block production, transaction ordering
Sources were accessed 2026-08-19. Primary documents and measured control conditions can change; the review triggers above govern off-cycle reassessment.