PostGuard: Towards Easy and Secure Email Communication
Leon Botros, Merel Brandon, Bart Jacobs, Daniel Ostkamp, Hanna Schraffenberger, Marloes Venema · 2023
This paper presents PostGuard: a secure email encryption solution for communication in the private and public sectors. The novelty of PostGuard lies in the combination of identity-based encryption with a digital identity wallet. Within this setting, senders specify who should be able to read/decrypt their emails in terms of the recipient’s attributes (e.g., their name and/or email address). Subsequently, recipients use the digital identity wallet app Yivi to prove that they possess these attributes to decrypt the mails. Thus, PostGuard reduces decryption to authentication. The underlying mental model is: to see confidential information, you need to prove that you are the intended recipient. The main contribution of this paper is the working prototype of PostGuard for Outlook and Thunderbird. This paper describes the concept, setup, implementation, and design of PostGuard and discusses current limitations and plans for future work.