Consensus

Parano1d accepts only blocks that satisfy the native header rules, the recursive HistoryStep relation and proof of work. Chain selection compares cumulative work among valid candidates while preserving the hard-finalized prefix.

The source code is the canonical consensus definition. This specification describes the stable rule set and its boundaries.

Candidate validity

For a child block to extend a parent, all of the following must hold:

1. prev_block_hash equals the parent's nonce-bearing block ID.
2. height is exactly parent.height + 1.
3. the timestamp is greater than the median of the preceding 11 headers and no more than 120 seconds ahead of local wall clock;
4. difficulty_target is the exact ASERT target derived from canonical history and is not easier than the protocol floor;
5. the Poseidon2b PoW digest is strictly less than the little-endian target;
6. the physical block encoding and all transaction groups are canonical;
7. the mandatory primary reward and any scheduled development payout are exact;
8. transaction-epoch anchors are current;
9. no input or output conflict exists inside the block;
10. fees, value conservation, allocation counters and slot writes are exact;
11. log_slots follows the finalized expansion rule;
12. the post-State counters and root equal the header commitments;
13. the supplied HistoryStep terminal verifies and binds the nonce-free semantic header.

The block and terminal are accepted as one bundle. A valid block without its matching terminal is not an accepted consensus object.

Fork choice

Every valid header contributes work derived from its target. The canonical chain is the candidate with the greatest cumulative work.

If two candidates have equal cumulative work, the chain with the lexicographically smaller tip block hash wins. The tie-break is deterministic; arrival order and peer identity have no role.

Hard finality

The most recent 18-block window is the only reorganizable part of the chain. A candidate that would change the finalized prefix is ineligible for fork choice. Because rollback depth must be strictly less than 18, the maximum accepted reorganization is 17 blocks.

Hard finality also separates State-expansion measurements from temporary forks. The 18-header occupancy window used for expansion ends at the finalized boundary, not at the tip.

This is a protocol rule, not a social checkpoint. All nodes derive the same boundary from height and reject deeper alternatives.

Difficulty

The target block interval is 15 seconds. ASERT adjusts the target using six-block reference epochs and a 90-second half-life. The target is encoded as a 256-bit little-endian integer.

Validation derives the one exact target from canonical header history. Miners do not choose among a range of acceptable difficulties.

Transaction clock

User transactions bind to a block ID at the start of a 144-block transaction epoch. The boundary block still accepts the preceding anchor; the new anchor becomes active for the next child.

For child height C > 0, the anchor height is:

floor((C - 1) / 144) × 144

This clock is independent of the six-block ASERT epoch. It limits replay and stale mempool lifetime without tying wallet authorization to every new State root.

Local policy is not consensus

Nodes may choose which admissible transactions to relay or mine. The default mempool uses minimum and dynamic fee policy, conflict reservations and bounded resources. Those choices cannot make a transaction invalid once it appears in a valid block, except where the same minimum fee formula is explicitly checked by consensus.

Likewise, mining requires two authenticated peers in the official node. That is an operational isolation guard, not a block-validity vote.

Genesis and network identity

The public network has one compiled chain origin, network magic and protocol identifier. A node does not negotiate consensus parameters with peers. Data from another network fails parent, identity or proof checks before it can become canonical State.

Continue with Blocks and headers, Transaction protocol, State transition, and the consensus invariant map.