This volume constitutes the refereed proceedings of the 13th IFIP WG 11.2 International Conference on Information Security Theory and Practices, WISTP 2019, held in Paris, France, in December 2019.The 12 full papers and 2 short papers presented were carefully reviewed and selected from 42 submissions. The papers are organized in the following topical sections: authentication; cryptography; threats; cybersecurity; and Internet of Things.