The BACK IN TIME Project: A User-Centred Platform for Encrypted Historical Documents

Abstract

Since the Late Middle Ages, sensitive correspondence (political, diplomatic, military, etc.) has frequently been encrypted. Thousands of these documents now lie in archives and libraries, yet they remain largely beyond the reach of humanities researchers. The sheer volume and complexity of these materials render both manual cryptanalysis and manual analysis impractical, if not impossible. Although recent advances in historical cryptanalysis and artificial intelligence have enabledpartial automation, existing tools remain ill-suited to the needs and practices of humanities researchers. The BACK IN TIME project was established in late 2024 to address these challenges. It seeks an alternative approach to automation that places the end user – namely, the humanities researcher – at the centre of the system’s design. In this paper, we articulate our vision for a user-centred assistive platform intended to bridge the current gap: we highlight how the guiding principles identified by the project team can be used to combine computer vision, cryptanalysis, and historical expertise into a user-centred design that makes historical cryptanalysis both accessible and compatible with established scholarly practices. Initial implementations will focus on Western European scripts and languages, as well as on manually encrypted documents (up to the early 20th century), reflecting the team’s expertise and easier access to these documents.