The most common computer authentication method is to use alphanumerical usernames and passwords. This method has been shown to have significant drawbacks. For example, users tend to pick passwords that can be easily guessed. On the other hand, if a password is hard to guess, then it is often hard to remember. To address this problem, some researchers have developed authentication methods that use pictures as passwords. In this paper, I conduct a comprehensive survey of the existing graphical password techniques. I classify these techniques into two categories: recognition-based and recall-based approaches. I discuss the strengths and limitations of each method and point out the future research directions in this area. I also developed three new techniques against the common problem exists in the present graphical password techniques. In this thesis, the scheme of each new technique will be proposed; the advantages of each technique will be discussed; and the future work will be anticipated.

No description available.

Given that phishing is an ever increasing problem, a better authentication system than the current alphanumeric system is needed. Because of the large number of current authentication systems that use alphanumeric passwords, a new solution should be compatible with these systems. We propose a system that uses a graphical password deployed from a Trojan and virus resistant embedded device as a possible solution. The graphical password would require the user to choose a family photo sized to 441x331 pixels. Using this image, a novel, image hash provides an input into a cryptosystem on the embedded device that subsequently returns an encryption key or text password. The graphical password requires the user to click five to eight points on the image. From these click-points, the embedded device stretches the graphical password input to a 32- character, random, unique alphanumeric password or a 256-bit AES key. Each embedded device and image are unique components in the graphical password system. Additionally, one graphical password can generate many 32-character unique, alphanumeric passwords using its embedded device which eliminates the need for the user to memorize many passwords. / Computer Engineering

There is a dilemma between security and usability, which are two fundamentally conflicting issues. From the usability perspective, authentication protocols should be easy to use and passwords generated from these protocols should be easy to remember. From the security perspective, passwords should be hard to guess and should not be written down or stored in a plain text. Instead of using text based passwords, graphical passwords have been proposed to increase both memorability and security. Biederman (1972) and Biederman, Glass, &amp / Stacy (1973) reported that the objects in a coherent image were recognized and identified more efficiently and quickly than the objects in a jumbled image in which the jumbled image was created by dividing the coherent image into sections and changing the position of the sections without rotating them. The study was designed to experimentally examine the differences in usability and security of the graphical password scheme by manipulating the coherence of the displayed image. Sixty-three volunteers participated in the main experiment. The participants were divided into groups according to the type of image they were presented in the password creation (either coherent-image or jumbled-image) task. Each participant created a graphical password and three days after the first session (i.e., second session) s/he tried to remember it in order to authenticate to the system. The results revealed that in the proposed graphical password scheme, using coherent image has more advantages over jumbled image in terms of usability and security.

No description available.

The focus of this report is to discuss graphical password systems and how they can contribute to handle security problems that threaten authentication processes. One such threat is shoulder-surfing attacks, which are also reviewed in this report. Three already existing systems that are claimed to be shoulder-surfing resilient are described and a new proposed system is presented and evaluated through a user study. Moreover, the system is compared to the mentioned existing systems to further evaluate the usability, memorability and the time it takes to authenticate. The user study shows that test subjects are able to remember their chosen password one week after having registered and signed in once. It is also shown that the average time to sign in to the system after five minutes of practice is within a range of 3.30 to 5.70 seconds. The participants in the experiments gave the system an average score above 68 on the System Usability Scale, which is the score of an average system.