Transaction protocol

The user transaction is one canonical logical PagedSpend. It consists of one to 128 fixed Tx8x2 pages and exactly one detached authorization capsule.

Physical page

Each page has the fixed 323-byte body encoding:

Bits 0–7 select inputs and bits 8–9 select outputs. Bits 10 and 11 mark the start and end of a logical group. No other bitmap bit may be set.

A record whose live bit is zero must be the all-zero canonical dummy. This removes alternate encodings of the same statement.

Group validity

A valid PagedSpend satisfies all of these rules:

• page count is between one and 128;
• only page zero has the start marker;
• only the final page has the end marker;
• every page has the same input_owner and epoch_anchor;
• only the first page carries a non-zero fee;
• live inputs and outputs are packed densely in page order;
• the page count is minimal for those records;
• at least one input is live;
• no input appears twice;
• no output slot appears twice;
• an output slot is not also an input slot in the same spend;
• there are at most 1,020 inputs and 256 outputs;
• total input value equals total output value plus the fee;
• the detached authorization is no larger than 256 KiB.

The maximum canonical intent encoding is 303,495 bytes.

Logical transaction ID

Page-local body hashes do not independently name the payment. The logical ID is a domain-separated Poseidon2b sponge over:

version || page_count || ordered_page_hashes

The launch version is 1. Reordering, adding or removing a page changes the ID. The authorization capsule proves knowledge of the preimage behind input_owner for that exact logical ID.

State checks

For each input, the current slot must be occupied by the declared owner, amount and creation_id. For each output, the target slot must be empty and inside the active slot domain.

Output creation_id values are not transaction fields. Consensus assigns them from the post-State allocation sequence. A user cannot choose or reuse one.

The block transition enforces all State checks atomically for the complete logical group.

Fees

The minimum fee is:

5,000
+ 100 × live_inputs
+ 700 × live_outputs
+ growth_price × max(0, live_outputs - live_inputs)

All amounts are in μNOID. growth_price begins at 2,500 μNOID per net-new slot and is multiplied by 1, 2, 4 or 8 according to parent-State occupancy.

The State-growth component is burned. Any fee above the required minimum is a miner-claimable tip. State-preserving and State-shrinking spends have no growth burn.

Epoch anchor

Every page uses the current transaction-epoch anchor. For child height C, the anchor is the block ID at:

floor((C - 1) / 144) × 144

for C > 0. Height 144 still consumes the height-zero anchor; height 145 begins using height 144. The mempool removes intents whose anchor is no longer current.

Authorization and State are separate

Wallet authorization proves ownership only. It does not prove current slot membership and contains no Live State Merkle path.

The block HistoryStep proves current membership, emptiness, balance, allocation and the post-State root. Both statements bind the same public logical transaction.

System records

Primary reward and scheduled development payout records use the fixed physical body type but are not user PagedSpend intents. Their shape, placement, recipients and amounts are derived entirely from block context. They carry no wallet authorization.

See Transaction architecture for wallet and mempool flow.