Department of Computer Science and Engineering Department of Electronic, Electrical and Computer Engineering Department of Electronic, Electrical and Computer Engineering Department of Electronic, Electrical and Computer Engineering This document proposes a scheme of security policy translation (i.e., Security Policy Translator) in Interface to Network Security Functions (I2NSF) Framework. When I2NSF User delivers a high-level security policy for a security service, Security Policy Translator in Security Controller translates it into a low-level security policy for Network Security Functions (NSFs). For this security policy translation, this document specifies the mapping between a high-level security policy based the Consumer-Facing Inteface YANG data model and a low-level security policy based on the NSF-Facing Interface YANG data model. Also, it describes an architecture of a security policy translator along with an NSF database, and the process of security policy translation with the NSF database.