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Open Assets
An asset protocol of coloured outputs that BTI decodes itself with a coloured-UTXO walk; B/A 0.72 in the July 2026 measurement run.
Open Assets 0.02 % of the chain's bytes in Book A, as of block 972,299, 2026-10-20 09:30:48 UTC
Open Assets is a ledger-protocol family in BTI's token table. Its tokens are Open Assets assets, each identified by an issuer-scoped asset id. BTI is its indexer: it is a native protocol, decoded by BTI's own openassets decoder with no external service between.
How Open Assets writes to Bitcoin #
The sources describe one carrier: an OP_RETURN output beginning with the Open Assets marker 4f410100. In case 18 of the BTI case studies, an issuance's marker output is 49 bytes, and its metadata is a URL (u=https://cpr.sm/…, a Coinprism definition). The asset's definition lives at that URL, not on chain, so the issuance carries no content region.
How BTI attributes its bytes #
The decoder runs in replay mode, a coloured-UTXO walk: the state it keeps to process each next block includes the coloured outpoints. The roster records one hard constraint: "a mid-chain cold start misclassifies 52–92% of OA txs".
Case 18 is the transaction that forced regions into BTI's schema (ruling A2). One 423-byte transaction is an Open Assets issuance with CoinSpark units drifting through it on CoinSpark's default route. The issuance is dedicated and claims the whole transaction; the CoinSpark claim declares only carrying structure, with dedication None. The two overlap on some atoms and not on others, and no single number per claim can express that. Divided by atom, Open Assets takes 253 bytes in Book B and the CoinSpark claim 170. The CoinSpark bytes become carriage, so Open Assets' Book A is 253, not 423, even though it was the transaction's only dedicated claimant. The case studies call this the canonical mixed-transaction fixture, "the single easiest place for a rebuild to 'fix' conservation in the wrong direction".
The token table records how Open Assets decays: "by total uncolouring".
The BTI protocol review of 2026-08-29 tested that decay label against the data and refuted it: 78.2 % of units had uncoloured, but only 0.89 % of assets, and 114,602 coloured outputs were still live. The same review found Open Assets and Colu answering one question in opposite ways: when a protocol-unaware spend destroys the colour, Open Assets declares the claim None (zero in every book) while Colu declares it riding.
The free-ride index #
In the July 2026 measurement run, Open Assets measured B/A = 0.72: in the measurements document's words, "29% of its inclusive claim is riding on payments that were happening anyway". The free-ride index is Book B ÷ Book A, the share of a family's inclusive claim that is its own measured structure. See carriage and the free-ride index.
The August review's own table read Open Assets' B/A as 0.9992 on the books then covering up to block 959,999. The two readings come from different runs, and the July figure is the one the measurements document publishes.
Live figures #
Open Assets holds 0.12 GB in Book A, 0.02 % of the chain's bytes and 0.09 % of all Book A. Its Book C is 0 bytes. The books count 55,179 assets across 260,766 operations, from block 299220 to 972256 (as of block 972,299, 2026-10-20 09:30:48 UTC).
The BTI handoff of 2026-08-16 recorded 119 MB for Open Assets in the books then covering blocks 0 to 779,999.
Related #
Sources #
Live figures: protocols as of block 972,299, 2026-10-20 09:30:48 UTC. Refreshed hourly.
Updated 2026-10-20 · This page as Markdown