"This white paper is the result of a series of discussions among insurers, chief information security officers (CISOs), and other cybersecurity professionals on perceived obstacles to the voluntary and anonymized sharing of cyber incident data into a trusted repository. These deliberations were conducted within the framework of the Cyber Incident Data and Analysis Working Group (CIDAWG) and facilitated by the Department of Homeland Security's (DHS) National Protection and Programs Directorate (NPPD). […] This white paper: (1) identifies eight perceived obstacles to the voluntary sharing of cyber incident data; (2) describes ways in which each obstacle might manifest in terms of questions or concerns that repository participants might have; (3) suggests approaches to addressing those questions and concerns in order to overcome each obstacle; and (4) identifies possible stakeholders and subject matter experts who could help develop and implement those approaches. The identified obstacles focus primarily on assured privacy and anonymization, data security, and technical design challenges. Approaches to address these issues involve process and communications strategies and technical best practices that should inform any future repository implementation. This latter category includes effective input mechanisms for sharing cyber incident data into a repository -- specifically, mechanisms that are easy to use, consistent with all applicable privacy and anonymization mandates, and relevant to stakeholders who will both contribute to the repository and utilize aggregated repository data for cyber risk analysis."