# Bitcoin Exposure Measure Sorts Supply by Public-Key Visibility By Simon Yoon Canonical URL: https://www.tokenpost.com/news/technology/54051 Published: 2026-11-11T14:05:05.000Z Updated: 2026-11-11T14:05:05.000Z Section: Technology > Its six categories include Taproot, P2PK and previously spent addresses. The measure refreshes monthly using month-end supply. Bitcoin's on-chain quantum-exposure measure sorts holdings by whether their controlling public keys are already visible on the blockchain, grouping supply by exposure to potential quantum attacks. Five categories mark exposed supply: Taproot outputs; P2PK outputs attributed to Satoshi Nakamoto; other P2PK outputs; previously spent exchange addresses; and previously spent addresses elsewhere. The sixth category covers all remaining supply. The categories are mutually exclusive and together account for the total supply. Each observation reflects supply at month-end, and the measure refreshes monthly. Exchange and Satoshi Nakamoto holdings are identified through entity clustering, so historical classifications can change when that clustering is updated. [Bitcoin output types reveal public keys in different ways](), while the address-reuse categories track holdings at addresses that have already spent an output. ## Links in this article - [Bitcoin output types reveal public keys in different ways](https://www.tokenpost.com/news/technology/27549)