Encouraging users to improve password security and memorability

Security issues in text-based password authentication are rarely caused by technical issues, but rather by the limitations of human memory, and human perceptions together with their consequential responses. This study introduces a new user-friendly guideline approach to password creation, including persuasive messages that motivate and influence users to select more secure and memorable text passwords without overburdening their memory. From a broad understanding of human factors-caused security problems, we offer a reliable solution by encouraging users to create their own formula to compose passwords. A study has been conducted to evaluate the efficiency of the proposed password guidelines. Its results suggest that the password creation methods and persuasive message provided to users convinced them to create cryptographically strong and memorable passwords. Participants were divided into two groups in the study. The participants in the experimental group who were given several password creation methods along with a persuasive message created more secure and memorable passwords than the participants in the control group who were asked to comply with the usual strict password creation rules. The study also suggests that our password creation methods are much more efficient than strict password policy rules. The security and usability evaluation of the proposed password guideline showed that simple improvements such as adding persuasive text to the usual password guidelines consisting of several password restriction rules make significant changes to the strength and memorability of passwords. The proposed password guidelines are a low-cost solution to the problem of improving the security and usability of text-based passwords

Integrating Visual Mnemonics and Input Feedback with Passphrases to Improve the Usability and Security of Digital Authentication

The need for both usable and secure authentication is more pronounced than ever before. Security researchers and professionals will need to have a deep understanding of human factors to address these issues. Due to their ubiquity, recoverability, and low barrier of entry, passwords remain the most common means of digital authentication. However, fundamental human nature dictates that it is exceedingly difficult for people to generate secure passwords on their own. System-generated random passwords can be secure but are often unusable, which is why most passwords are still created by humans. We developed a simple system for automatically generating mnemonic phrases and supporting mnemonic images for randomly generated passwords. We found that study participants remembered their passwords significantly better using our system than with existing systems. To combat shoulder surfing - looking at a user\u27s screen or keyboard as he or she enters sensitive input such as passwords - we developed an input masking technique that was demonstrated to minimize the threat of shoulder surfing attacks while improving the usability of password entry over existing methods. We extended this previous work to support longer passphrases with increased security and evaluated the effectiveness of our new system against traditional passphrases. We found that our system exhibited greater memorability, increased usability and overall rankings, and maintained or improved upon the security of the traditional passphrase systems. Adopting our passphrase system will lead to more usable and secure digital authentication

Towards Human Computable Passwords

An interesting challenge for the cryptography community is to design authentication protocols that are so simple that a human can execute them without relying on a fully trusted computer. We propose several candidate authentication protocols for a setting in which the human user can only receive assistance from a semi-trusted computer --- a computer that stores information and performs computations correctly but does not provide confidentiality. Our schemes use a semi-trusted computer to store and display public challenges $C_i\in[n]^k$. The human user memorizes a random secret mapping $\sigma:[n]\rightarrow\mathbb{Z}_d$ and authenticates by computing responses $f(\sigma(C_i))$ to a sequence of public challenges where $f:\mathbb{Z}_d^k\rightarrow\mathbb{Z}_d$ is a function that is easy for the human to evaluate. We prove that any statistical adversary needs to sample $m=\tilde{\Omega}(n^{s(f)})$ challenge-response pairs to recover $\sigma$, for a security parameter $s(f)$ that depends on two key properties of $f$. To obtain our results, we apply the general hypercontractivity theorem to lower bound the statistical dimension of the distribution over challenge-response pairs induced by $f$ and $\sigma$. Our lower bounds apply to arbitrary functions $f$ (not just to functions that are easy for a human to evaluate), and generalize recent results of Feldman et al. As an application, we propose a family of human computable password functions $f_{k_1,k_2}$ in which the user needs to perform $2k_1+2k_2+1$ primitive operations (e.g., adding two digits or remembering $\sigma(i)$), and we show that $s(f) = \min\{k_1+1, (k_2+1)/2\}$. For these schemes, we prove that forging passwords is equivalent to recovering the secret mapping. Thus, our human computable password schemes can maintain strong security guarantees even after an adversary has observed the user login to many different accounts.Comment: Fixed bug in definition of Q^{f,j} and modified proofs accordingl

Security and usability in password authentication

This thesis investigates the human-factor problems in password authentication and proposes some usable solutions to these problems by focusing on both forms of knowledge based authentication: textual passwords and graphical passwords. It includes a range of empirical studies to examine users' password-related behaviour and practices in authentication, and helps users to adopt secure password behaviour. This thesis consists of two parts. The first part focuses on traditional text-based passwords. Design flaws and usability issues of existing text-password mechanisms used by many organisations cause employees to adopt insecure password practices. The first work in this thesis investigates the reasons for employees' lack of motivation regarding password protection against security failures. An empirical study is conducted to identify the factors causing employees’ insecure behaviours in organisations, and several persuasion strategies are tested to persuade employees to use passwords more safely. The results of the study revealed that some persuasion strategies are effective in motivating users to adopt good password practices. The study also found that the failure of password policies and authentication schemes deployed by organisations is a common problem among the organisations. Considering the results of the first study, in the second work of this thesis, a password guideline/advice study is conducted to help users to create stronger and more memorable passwords. A password guideline including a number of password creation methods and a persuasive message is proposed, and its effectiveness in improving the strength of user-chosen passwords is evaluated. The results show that the users who received the proposed guideline produced stronger and more memorable passwords than the users followed the usual password restrictions while creating their passwords. The results also demonstrate that the given password creation methods can be helpful and inspirational for users to create their own encryption formula. All these works reveal the weaknesses of user-chosen textual passwords and inefficacy of existing text-based password mechanisms. Although these studies show that text-based password mechanisms can be strengthened, they are still problematic where usability is concerned. Thus, the second part of this thesis focuses on another form of knowledge-based authentication: graphical passwords. A novel hybrid authentication scheme integrating text and images is introduced to minimise the brute force and shoulder surfing attacks which text and graphical passwords suffer. In the last work of this thesis, the proposed hybrid scheme is implemented and evaluated. The evaluation shows that the proposed scheme provides security and usability at the same time, and it also makes the password creation process enjoyable for users. In summary, the thesis contributes to the analysis of some key security and usability problems which arise in knowledge-based authentication. A series of empirical studies has been conducted. Based on their results, usable solutions to the human-factor problems in password-based authentication are proposed and evaluated

Short-term and Long-term Effects of Fear Appeals in Improving Compliance with Password Guidelines

Passwords are the most widely used method of authentication on the Internet, but users find compliance with password guidelines difficult, and we know little about the long-term effects of attempts to improve compliance. In this paper, we extend the work of fear appeals use in the IS security domain to investigate their longer-term effects. We conducted a longitudinal experimental study to examine fear appeals’ long- and short-term effects. Using a model based on protection motivation theory (Rogers, 1983), we found that fear of threat, perceived password effectiveness, and password self-efficacy predicted compliance. We also found that neither perceived vulnerability to a security attack nor perceived severity of an attack influenced compliance. Providing persuasive communication improved compliance with password guidelines and resulted in significantly stronger passwords, but the effects on compliance intentions were only short term. This study extends our understanding of the factors that influence compliance with password guidelines and how we can modify them to improve compliance. We raise interesting questions about the role of fear in different IS security contexts. We also highlight the need for more research on the long-term impact of persuasive communication

A protection motivation theory approach to improving compliance with password guidelines

Usernames and passwords form the most widely used method of user authentication on the Internet. Yet, users still find compliance with password guidelines difficult. The primary objective of this research was to investigate how compliance with password guidelines and password quality can be improved. This study investigated how user perceptions of passwords and security threats affect compliance with password guidelines and explored if altering these perceptions would improve compliance. This research also examined if compliance with password guidelines can be sustained over time. This study focuses on personal security, particularly factors that influence compliance when using personal online accounts. The proposed research model is based on the Protection Motivation Theory (PMT) (Rogers, 1975, 1983), a model widely used in information systems security research. As studies have failed to consistently confirm the association between perceived vulnerability and information security practices, the model was extended to include exposure to hacking as a predictor of perceived vulnerability. Experimental research was used to test the model from two groups of Internet users, one of which received PMT based fear appeals in the form of a password security information and training exercise. To examine if password strength was improved by the fear appeals, passwords were collected. A password strength analysis tool was developed using Shannon’s (2001) formula for calculating entropy and coded in Visual Basic. Structural equation modeling was used to test the model. The proposed model explains compliance intentions moderately well, with 54% of the variance explained by the treatment model and 43% explained by the control group model. Overall, the results indicate that efficacy perceptions are a stronger predictor of compliance intentions than threat perceptions. This study identifies three variables that predict user intentions to comply with password guidelines as particularly important. These are perceived threat, perceived password effectiveness and password self-efficacy. The results show no association between perceived vulnerability to a security attack and a user’s decision to comply. The results also showed that those who are provided with password information and training are significantly more likely to comply, and create significantly stronger passwords. However, the fear appeals used in this study had no long-term effects on compliance intentions. The results on the long-term effects of password training on the participants’ ability to remember passwords were however promising. The group that received password training with a mnemonic training component was twice as likely to remember their passwords over time. The results of this research have practical implications for organizations. They highlight the need to raise the levels of concern for information systems security threats through training in order to improve compliance with security guidelines. Communicating to users what security responses are available is important; however, whether they implement them is dependent on how effective they feel the security responses are in preventing an attack. Regarding passwords, the single most important consideration by a user is whether they have the ability to create strong, memorable passwords. At the very least, users should be trained on how to create strong passwords, with emphasis on memorization strategies. This research found mnemonic password training to have some long-term effects on users’ ability to remember passwords, which is arguably one of the most vexing challenges associated with passwords. Future research should explore the extent to which the effects of PMT based information systems security communication can be maintained over time

553 Issues in Information Systems

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