. . "2019-06-08" . "Sharing Cyber Threat Intelligence under the General Data Protection Regulation"^^ . . . . . . . . "11498" . . . . . . . . "Sharing Cyber Threat Intelligence (CTI) is a key strategy for improving cyber defense, but there are risks of breaching regulations and laws regarding privacy. With regulations such as the General Data Protection Regulation (GDPR) that are designed to protect citizens\u2019 data privacy, the managers of CTI datasets need clear guidance on how and when it is legal to share such information. This paper defines the impact that GDPR legal aspects may have on the sharing of CTI. In addition, we define adequate protection levels for sharing CTI to ensure compli- ance with the GDPR. We also present a model for evaluating the legal require- ments for supporting decision making when sharing CTI, which also includes advice on the required protection level. Finally, we evaluate our model using use cases of sharing CTI datasets between entities."^^ . . . . . . . . . . . .