Toward Tactile Authentication for Blind Users Shiva Sharma, Information Systems Faculty Mentor: Dr.Ravi Kuber Email: firstname.lastname@example.org Abstract A tactile authentication system has been developed to address the challenges faced by blind users when entering passwords to access personal information stored in electronic format. Issues commonly encountered include inaccessible feedback presented by systemsand the risk of third parties viewing passwords whilst being entered, thereby compromising security. Users will enter a ‘tactile password’, comprised of four pin patterns presented via cells on a tactile mouse. As the pin patterns are presented beneath the fingertips, they are accessible by a wide range of users, and hidden from ‘shoulder surfers’. A study will be undertaken to identify whether the tactile stimuli are memorable and examine usability of the interface. Figure 1. Grid squares containing tactile stimuli Figure 2. VT Player (Virtouch Ltd) Figure 3. Examples of pin patterns which form an Figure 4. Different tactile stimuli are authentication sequence temporally presented within one square INTRODUCTION Information technology has been the essential part of our life. As we all know, technology is changing every day becoming ever more complex and enormous. Technology should be designed to simplify the complexity that users face. It is even more difficult for blind users who have to depend heavily on technology to perform normal activities that we take for granted. Along with the technology come the larger issues about its security and privacy. How blind users can preserve their security and how technology can help them is another critical part of today’s information technology. We all know that no system is 100% secure and reliable .There are constant threats to all users, from blind to normal users. For blind users, this is an even bigger concern. They have to depend on assistive technology to perceive the information. Our research tried to find a way to improve the exchange of information by blind users through the use of assistive devices like the tactile mouse. We examined how a better interface, system feedback, sense of touch and reliable system can bridge the gap between security and reliability that most of the blind users find challenging in today’s fast moving world. After testing users for a month we found interesting facts about the users’ interaction with the TAS system. In this study, we asked two set of questions, one usability related and one authentication experience related. These questions were an important part of the study. Described below are the users’ educational background, work experience, computer experience and usability related analysis. The users were asked to choose four tactile sensations from a choice of 36 pin patterns during an enrollment procedure. These pin patterns are distinct from one another, allowing each user to differentiate between the stimuli. The four tactile sensations selected by the users were saved in sequence order within the database. Users were given several practice sessions before they selected their final password. Procedure: Step 1) User creates his/her profile/selects his/her name from the profile Step 2) User is presented with a rage of tactile stimuli. Each stimulusi is randomized and changed every 5 seconds. User chooses 4 sets of tactile stimuli. Step 3) User is presented with a memorization screen so that they can remember their password order and pattern before they finally attempt their password. Step 4) User enters the correct password to verify their valid authentication. If user can identify the correct pin patterns the system is accessible. In the case of more than 3 failed attempts, system prompts user to change his/her password. User demographics The participants were selected according to their age, computing experience and educational background. Due to the differences in these areas, users described the TAS experience differently. Users age 20-39 spent less time selecting their password after they were trained. When we asked why they were spending less time in selecting the password, they mentioned that they are comfortable remembering the pin pattern that appears in the beginning of the stage. The users mentioned that the system was user friendly. Audio feedback was essential for them because as they were making progress on each stage, they felt the audio feedback helped them track their current stage and know how many stages were left. Users age 40-59 took more time selecting their password and they tried to feel the pins as much as possible. They used this strategy so that they could choose patterns that were easier to remember. When the users were asked to describe their password after they selected it, most of the users used hand movements to describe their password. Some of them even described animated pin pattern with sounds like zzzzzzz, uuuuu. Even though most of the users used one or two similar password numbers, they described it in a completely different manner. Users describing their experience differently were one of the key factors for this study. It shows that users with different ages, educational backgrounds and computing experience can describe the same thing in very different ways. Table 1: User age Age No of users 20-29 12 30-39 1 40-49 2 50-59 1 Table 2: Highest Education Level Highest Education Level Some high school 2 High school graduate 2 College 4 College graduate 8 Table 3: Computer experience and use of technology Computer user No of participants Normal 1 Intermediate 2 Advanced 11 Never used computer 2 Recognition vs. Recall During the study we asked the users how they picked their tactile password and what method they used to remember their password using the tactile mouse. Most of the users mentioned that they picked their tactile password using the following factors: 1) By selecting minimum or maximum pin movement. 2) By selecting all static pins or all animated pins. 3) By thinking in their mind and making patterns. Users used the recognition method to retrieve their password. During the password entry phase, they mentioned that they could recognize their pin when they were allowed to choose it. Users were usually confused when they had similar types of pins randomly generated by the system. They had trouble telling the difference between the similar patterns. Usability study One of the users mentioned that “the tactile mouse was too large to comfortably use, so I used a second (regular) mouse for my tests. Part of the trouble I had was using the second mouse with my left hand. Some of the mistakes I made were because I had to remember to use that hand, which delayed my response enough that I clicked on the pin pattern after mine. If the mouse can be made less cumbersome to use, I think the pin pattern system will help blind users securely enter passwords.” Most of the users shared a similar story. Since they normally used a single small mouse to accomplish their computing tasks, the size of the tactile mouse and navigating one mouse with each hand created confusion. They recommended that using a small tactile mouse would help users successfully enter the password. Then we asked users about their user experience and whether this system would benefit blinds users. Almost all users had a positive response to this question. They mentioned that the system will be helpful to blind users because its voice feedback when user performs the action will tell the users where they are and what they are doing within the system. Users added that since the mouse is designed for the blind and most of the blind users use Braille devices it could be easily incorporated. Security Users mentioned that because the pin movements are hidden under the user’s finger tips, it makes the system secure from shoulder surfing. They still felt that the system can be improved by adding more security features like storing passwords in a database or by using data encryption methods so if someone hacked into the system the person could not figure out the user’s password. Average time taken by users Average time: During the first week, the average was 130.4 seconds Average time: During the second week, the average time was 136.546 seconds Average time: During the fourth week, the average time was 136.14 seconds Over the four weeks of the testing period, users never requested to reset their password and none of the users asked to change their password. Users selected their password carefully. They never clicked randomly; they made sure to select pin patterns that could be remembered for a long time. When pin patterns were randomized, everyday users were still able to recognize their password. They even mentioned that the pin pattern had been changed and knew that the pins were in a different order. This shows that users are recognizing the pin patterns themselves rather than recalling it by the sequence of patterns. It was interesting to see the facial expressing on users as they were using the mouse. Some of the users closed their eyes to recognize their password, while other users looked in the opposite direction while they were entering their password. Number of attempts weekly Week 1 second attempts: 0 users Week 2 second attempts: 5 times Week 4 there were no second or third attempts by any users. Final week comparison During the first week, the users had some navigation problems with the tactile mouse. Users were having trouble navigating the system with multiple mice. The average time for week 1 was less than the time for week 2. The final week average time was 136 seconds. The average time was so long because users were waiting to complete one whole cycle of each stage and because of the size of the mouse. They were not able to click at the right time; as a result they missed their click and had to wait again to get back to their password. There are two reasons the users took a long time to enter their password on the final week. First, they had a two week gap between testing sessions. Second, the pin pattern was randomized in the final testing session. Users were very careful on their final week while entering their password. They were making sure they were selecting their correct password by spending more time with the system. Error made by users Users original password users entered Wrong number 1182135 6182135 6 1182135 4182135 4 1182135 4182135 4 3182333 3181933 19 2101931 3102331 3,23 2101931 3102331 3,23 2101931 4101931 4 2101931 2102331 23 2101931 2102331 23 7162033 9162033 9 2132131 3132131 2 1132129 4132129 4 Most of the users made mistake in their first stage. Above data shows that one user made a mistake by selecting the same wrong password twice. Many users selected number 4 and made mistakes. pin 4 vs. pin 1 Comparing pin1 and pin 4, it shows that users got confused because each set of pins is raised on the four corners and due to limited time they could not figure out the differences easily. pin 23 vs. pin 19 Comparing pin 23 and pin 19, it is clear why several users made mistakes on this pattern. They are almost identical and due to limited time to recognize patterns, most of the users failed. It proves that users made mistakes because they could not distinguish between patterns which are almost identical to each other. This problem can be resolved by generating pins which are completely different from each other. pin 2 vs. pin 3 The above pins are identical in nature but they are oriented in opposite directions. This creates confusion to the users who have a limited number of seconds to recognize the patterns. When these numbers are randomized, they frequently came one after the other which often made users more puzzled; as a result they made back to back mistakes. During the trial period sighted users were using extra caution while navigating with the tactile mouse and selecting their password. While blind users were very comfortable navigating with the mouse,it sighted users acted as if they had never used a mouse and such pin patterns, whereas blind users were comfortable with the tactile mouse. The main problem that blind users faced was animated pin patterns. Since pin patterns were randomized, sometimes animation patterns appeared back to back, which made it difficust for them to determine the difference between the two. Sighted users took more time to select and enter their password whereas blind users were quick in choosing and entering their password. This shows that blind users are comfortable with assistive technology. CONCLUSIONS AND FUTURE WORK The main problem with the system was navigating with two mice. Sometimes users did not click properly with a regular mouse; as a result they ended up making mistakes. Most mistakes were made due to mouse navigation rather than users not being able to recognize their password. Seeing those problems, I clicked for those users. Overall, all users responded that the system is beneficial for the blind and would help blind users. Users were interested to know when the system could be implemented for real-world use. The blind participants shared valuable information about the system. One participant mentioned that an animated pin pattern would be challenging to recognize. Adding more audio feedback would help the beginner and be useful for loud environments. Providing the ability to monitor audio options would be beneficial for users. This system is secure because all the interaction occurs beneath the fingertips of users. The password was easier to remember because it was short (only 4 patterns). It would be more difficult to remember the password if it were longer. Users felt that the authentication patterns should be more distinctive. The users had to wait a long time for their sequence to come up. In essence, this is a waste of time. In cases where security is paramount this can be used, as it is one of the most secure ways to access information. After interacting with the users over four weeks, I found that we still need to improve the quality of the system by adding more audio feedback, improving the interface design, making the system faster and more robust, and by adding more security features. Letting users perform tasks by themselves, for example by selecting their name from a dropdown menu to enter their password, would improve the users’ experience. It would be interesting to introduce a screen reader to read the content of the interface and ask users to navigate accordingly. After taking users’ comments into account, in the future we can come up with a better authentication system that would help visually impaired users access information without having to worry about security.
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