Cardano L1 Anchoring

Cardano L1 Anchoring — Metadata format for Materios checkpoint transactions

What Are Materios Anchor Transactions?

Every batch of certified receipts on the Materios chain is periodically checkpointed to Cardano mainnet as a metadata transaction. These anchor transactions carry a Merkle root covering all receipts in the batch, giving each receipt Cardano-grade finality without the cost of writing every receipt individually to L1.

• Metadata label 8746 is reserved for Materios receipt checkpoint anchors.

• The anchor worker submits a new checkpoint roughly every ~2 minutes when new receipts have been certified.

• Each anchor transaction costs approximately 0.18 ADA.

Metadata Format (v2)

All anchor transactions carry a JSON metadata payload under label 8746:

{
  "p": "materios",
  "v": 2,
  "chain": "5663079a485b93fdc9e386b862b4cf8d25499427df6b8c5f018535acfd2e5020",
  "root": "<merkle root of certified receipt batch>",
  "manifest": "<SHA-256 hash of batch manifest>",
  "blocks": [<from_block>, <to_block>],
  "leaves": <number of receipts in batch>
}

Field Definitions

Field	Type	Description
p	string	Protocol identifier. Always "materios".
v	int	Metadata schema version. Current: 2.
chain	string	Materios chain genesis hash (first 64 hex chars). Identifies which chain this anchor belongs to.
root	string	Merkle root of the checkpoint batch. SHA-256 hash covering all certified receipts in this batch.
manifest	string	SHA-256 hash of the batch manifest JSON (contains leaf hashes, block range, timestamps).
blocks	[int, int]	Materios block range [from, to] covered by this checkpoint.
leaves	int	Number of certified receipts included in this batch.

How to Verify

1. Find the TX on cexplorer. Search for the transaction hash at cexplorer.io. The metadata payload will be displayed under the transaction's metadata tab with label 8746.

2. Understand the Merkle structure. Each leaf in the Merkle tree is computed as:

   SHA-256("materios-checkpoint-v1" || chain_genesis || receipt_id || cert_hash)

   The root field in the metadata is the root of this tree.

3. Verify individual receipts. Download the batch manifest (referenced by manifest hash). The manifest contains the ordered list of leaf hashes. Recompute the leaf hash for the receipt you want to verify and confirm it is present in the manifest; then recompute the Merkle root from all leaves and compare it to the on-chain root.

4. Use the Materios Explorer. The explorer at materios.fluxpointstudios.com/explorer shows verification status for every checkpoint, including the corresponding Cardano TX hash and a direct link to cexplorer.

Example Transaction

First mainnet anchor with v2 metadata, submitted April 10, 2026:

TX hash: b2b55a984af345b3ae758d7c92ee033e3066b24c17b7b1755f07a30e9bababf3

View it on cexplorer: cexplorer.io/tx/b2b55a984af345b3ae758d7c92ee033e3066b24c17b7b1755f07a30e9bababf3

Anchor Frequency and Cost

Parameter	Value
Submission interval	~2 minutes (when new certified receipts exist)
Cost per anchor TX	~0.18 ADA
Metadata label	8746
Schema version	2