Title
Designing Password Policies for Strength and Usability.
Abstract
Password-composition policies are the result of service providers becoming increasingly concerned about the security of online accounts. These policies restrict the space of user-created passwords to preclude easily guessed passwords and thus make passwords more difficult for attackers to guess. However, many users struggle to create and recall their passwords under strict password-composition policies, for example, ones that require passwords to have at least eight characters with multiple character classes and a dictionary check. Recent research showed that a promising alternative was to focus policy requirements on password length instead of on complexity. In this work, we examine 15 password policies, many focusing on length requirements. In doing so, we contribute the first thorough examination of policies requiring longer passwords. We conducted two online studies with over 20,000 participants, and collected both usability and password-strength data. Our findings indicate that password strength and password usability are not necessarily inversely correlated: policies that lead to stronger passwords do not always reduce usability. We identify policies that are both more usable and more secure than commonly used policies that emphasize complexity rather than length requirements. We also provide practical recommendations for service providers who want their users to have strong yet usable passwords.
Year
DOI
Venue
2016
10.1145/2891411
ACM Trans. Inf. Syst. Secur.
Keywords
Field
DocType
Passwords, authentication, password-composition policy, usable security
Internet privacy,Password strength,Computer security,Computer science,Usability,Password psychology,Service provider,One-time password,Password policy,Password,Cognitive password
Journal
Volume
Issue
ISSN
18
4
1094-9224
Citations 
PageRank 
References 
24
0.96
41
Authors
10
Name
Order
Citations
PageRank
Richard Shay1107343.90
Saranga Komanduri2109541.21
Adam L. Durity31154.13
Phillip (Seyoung) Huh4742.48
Michelle L. Mazurek5105957.67
Sean M. Segreti624010.08
Blase Ur797348.81
Lujo Bauer82460120.71
Nicolas Christin92133126.02
Lorrie Faith Cranor106767515.80