The impact of length and mathematical operators on the usability and security of system-assigned one-time PINs

摘要: Over the last decade, several proposals have been made to replace common personal identification number, or PIN, with often-complicated but the- oretically more secure systems. We present a case study of one such system, specific implementation system-assigned one-time PINs called PassGrids. apply various modifications basic scheme, allowing us review usabil- ity vs. security trade-offs as function complexity authentication scheme. Our results show that most variations this PIN system are enjoyable and no difficult than PINs, although accuracy suffers for complicated variants. Some variants increase resilience against obser- vation attacks, number users who write down otherwise store their password increases shed light on extent which able willing tolerate complications au- thentication schemes, provides useful insights designers new schemes.