Usability Smells: An Analysis of Developers’ Struggle With Crypto Libraries

Green and Smith propose ten principles to make cryptography libraries more usable, but to what extent do the libraries implement these principles? We undertook a thematic analysis of over 2400 questions and responses from developers seeking help with seven cryptography libraries on Stack Overflow; analyzing them to identify 17 underlying usability issues and studying see how prevalent they were across the seven libraries. Mapping our usability issues to Green and Smith’s usability principles we identify 4 usability smells where the principles are not being observed. We suggest improvements library developers can make to reduce the smells and how we can make cryptography libraries more usable for all.