USA National Institute of Standards and Technology Fastly USA National Institute of Standards and Technology The Signed Prefix List (SPL) is an RPKI object that attests to the complete list of prefixes which an Autonomous System (AS) may originate in the Border Gateway Protocol (BGP). This document specifies an SPL-based Route Origin Verification (SPL-ROV) methodology and combines it with the ROA-based ROV (ROA-ROV) to facilitate an integrated mitigation strategy for prefix hijacks and AS forgery. The document also explains the various BGP security threats that SPL can help address and provides operational considerations associated with SPL-ROV deployment.