Beat Chain & VDF

What is a beat?

A beat is a single unit of verifiable sequential computation. Each beat is produced by iterating SHA-256 a fixed number of times (the difficulty):

seed = sha256(prev_hash : beat_index : nonce : anchor_hash)
beat = sha256(sha256(sha256(... seed ...)))  // D iterations

At difficulty D=1000, each beat requires 1,000 sequential SHA-256 hashes and cannot be parallelized within a single chain (each hash depends on the previous one).

Beats Service (Free Public Utility)

The Beats service (beats.provenonce.dev) is a free, public utility that produces the global anchor chain (one anchor per ~60 seconds) and writes anchors to Solana as memos.

It has no API keys, no accounts, and no per-agent identity.

Two Uses Of Beats (Phase 2)

1) Synthetic time for the whole protocol

The registry records critical events in beats:

• registered_at_beat
• sigil_issued_at_beat
• last_heartbeat_beat

Verifiers use beats to determine recency (market staleness) without trusting wall-clock time.

2) Sequential-work credits for spawning (temporal gestation)

Spawning is rate-limited by credited sequential work:

• The agent computes beats locally.
• The agent submits a compact proof to the registry.
• The registry verifies the proof via spot-check recomputation and credits the agent’s total_beats.

This is separate from heartbeats:

• Heartbeats are paid liveness proofs (SIGIL required).
• Heartbeats do not require the agent to compute beats.

What is a beat chain?

A beat chain is a sequence where each beat commits to the previous beat’s hash:

Beat 0 (genesis) -> Beat 1 -> Beat 2 -> ... -> Beat N

VDF property

The sequential nature of SHA-256 chaining means beats cannot be produced faster than one-at-a-time. This makes a beat chain VDF-like: proof that a specific amount of sequential computation was performed.

Provenonce uses the term “VDF” as established shorthand. Formally, the construction is an iterated sequential hash chain (SHA-256). It shares the sequential computation property with academic VDFs but uses spot-check sampling rather than O(1) proof verification.

Anchor hash weaving

Beat seeds include a recent global anchor hash. This prevents pre-computation of future beats without knowledge of future anchors.

The ANCHOR_HASH_GRACE_WINDOW (currently 5) limits valid anchors to the most recent anchors, giving minutes of tolerance.