{"ID":2870580,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2509.13405","arxiv_id":"2509.13405","title":"Defining Security in Quantum Key Distribution","abstract":"The security of quantum key distribution (QKD) is quantified by a parameter $\\varepsilon\u003e0$, which -- under well-defined physical assumptions -- can be bounded explicitly. This contrasts with computationally secure schemes, where security claims are only asymptotic (i.e., under standard complexity assumptions, one only knows that $\\varepsilon \\to 0$ as the key size grows, but has no explicit bound). Here we explain the definition and interpretation of $\\varepsilon$-security. Adopting an axiomatic approach, we show that $\\varepsilon$ can be understood as the maximum probability of a security failure. Finally, we review and address several criticisms of this definition that have appeared in the literature.","short_abstract":"The security of quantum key distribution (QKD) is quantified by a parameter $\\varepsilon\u003e0$, which -- under well-defined physical assumptions -- can be bounded explicitly. This contrasts with computationally secure schemes, where security claims are only asymptotic (i.e., under standard complexity assumptions, one only...","url_abs":"https://arxiv.org/abs/2509.13405","url_pdf":"https://arxiv.org/pdf/2509.13405v1","authors":"[\"Carla Ferradini\",\"Martin Sandfuchs\",\"Ramona Wolf\",\"Renato Renner\"]","published":"2025-09-16T18:00:01Z","proceeding":"quant-ph","tasks":"[\"quant-ph\",\"cs.CR\"]","methods":"[]","has_code":false}