Consensus Finality & Epoch-Anchored State Settlement

1. Solana's Base Consensus Layer

Solana Unchained is built on Solana, which uses Tower BFT — a Proof-of-History (PoH) enhanced Byzantine Fault Tolerant consensus. Key properties relevant to reorg handling:

• Blocks achieve optimistic confirmation after ~32 validator votes (~2–3 seconds)
• Blocks reach full finalization after a supermajority (>2/3 of stake) locks in via Tower BFT — approximately 13 seconds
• Deep reorgs (more than a few slots) are economically and cryptographically near-impossible due to exponential lockout penalties on validators who vote on conflicting forks

2. Epoch Structure on Solana

A Solana epoch spans approximately 432,000 slots (~2.5 days). At each epoch boundary:

• Validator stake weights are recalculated
• Leader schedules are rotated
• Staking rewards are distributed

For Solana Unchained's Vault and staking contracts, epoch boundaries act as settlement anchors — the point at which yield accrual, lock period progression, and reward distribution are finalized.

3. How Reorgs Are Handled at the Protocol Level

Scenario	Outcome
Short-range fork (1–4 slots)	Resolved by Tower BFT before epoch anchor is written; no impact on protocol state
Medium-range fork (pre-finalization)	Tower BFT lockout penalties prevent validators from switching; fork resolved within seconds
Post-finalization reorg	Cryptographically impossible — finalized blocks cannot be reversed under Tower BFT
Epoch boundary reorg	Cannot occur — epoch anchors are only written after underlying slots are finalized

By the time an epoch anchor is recorded, every slot within that epoch is already Tower BFT finalized. The epoch anchor is a downstream artifact of finalized state, not a consensus mechanism itself.

4. Protocol-Level Safeguards for Unchained Contracts

• All state-changing instructions require confirmed or finalized commitment level
• Yield snapshots reference epoch-boundary slot hashes, which are immutable post-finalization
• Lock period expirations are calculated using absolute slot numbers, not timestamps, to prevent clock drift manipulation