QERA: A Quantum Economic Risk Assessment Framework for Blockchain Cryptographic Infrastructure

Cryptocurrency as a medium of exchange and digital means of payment generated and stored electronically on a blockchain system, employing cryptographic techniques to verify the transfer of funds and an algorithm in order to control the formation of monetary units. In such systems, transactions are assembled in groups, known as blocks which are organized in a chronological sequence referred to as blockchain. Blocks are added to the chain by means of a mathematical process that makes it very difficult for an individual user to seize the blockchain, and correspondingly, progresses made in quantum computing serve for the long-term security considering the threats concerning the cryptographic algorithms currently used in blockchain applications. As the cryptocurrency market capitalization approaches $2.95 trillion in early 2026, the arrival of fault tolerant quantum computing threatens the cryptographic foundations of the digital economy. While Shor’s algorithm poses a systemic risk to the elliptic curve primitives securing Web3, existing risk models fail to account for the unique economic asymmetry of blockchain assets: the fixed computational cost of a cryptographic break versus the variable, high stakes financial rewards on-chain. This paper introduces the Quantum Economic Risk Assessment (QERA) framework, which is a quantitative model that ranks blockchain vulnerabilities by the ratio of extractable value to quantum computational cost [Formula: see text]. Through a component level mapping of the Ethereum and Bitcoin ecosystems, we demonstrate that a rational quantum adversary will not prioritize consensus level attacks which we prove to be economically irrational at a cost of $4.65 trillion but will instead target high value, single key assets. Our findings identify Satoshi era P2PK addresses (R=24,606), single admin DeFi protocols (R=8,517), and pairing based ZK rollups (R=3,155) as the most urgent targets for post quantum migration. QERA provides protocol designers and institutional stakeholders with a rigorous, adversary aligned roadmap for evidence based cryptographic transitions in the face of emerging quantum threats.