Syntactic Generation of Memorable Passwords

Most tools for generating alphanumeric passwords often combine string tokens without considering semantics, as semantics contribute to the remembrance of a password string. We propose a formal method for the generation of passwords with semantic annotations using context-free grammars. A context-free grammar is a system with which one can make an infinite set of strings or objects. Users are allowed to specify their interests (such as music, movie, etc.) and phrases from these interests are used, in combination with at most three digits and one special character, to generate memorable passwords. This idea is implemented in a software tool called PassGen. PassGen takes, as input user interests, and generate n passwords for the user to choose from. 20,000 samples of generated passwords can be found at https://tinyurl.com/SyntacticPassword2018. A Survey of twenty seven responses shows that eighteen respondents agree that a tool that generates memorable secure passwords suggestion for users to pick from will be useful, while fourteen respondents agree that some passwords we generated using context-free grammars are memorable.