• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.4
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• pp.903-910
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• 2016

As smart mobile devices having touchscreens are growingly deployed, a pattern lock system, which is one of the graphical password systems, has become a major authentication mechanism. However, a user's unlocking behaviour leaves smudges on a touchscreen and they are vulnerable to the so-called smudge attacks. Smudges can help an adversary guess a secret pattern correctly. Several advanced pattern lock systems, such as TinyLock, have been developed to resist the smudge attacks. In this paper, we study an automated smudge attack that employs machine learning techniques and its effectiveness in comparison to the human-only smudge attacks. We also compare Android pattern lock and TinyLock schemes in terms of security. Our study shows that the automated smudge attacks are significantly advanced to the human-only attacks with regard to a success ratio, and though the TinyLock system is more secure than the Android pattern lock system.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.280-290
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• 2016

In this paper, we propose a layered pattern authentication scheme resistant to social engineering attacks. Existing android pattern lock scheme has some weak points for social engineering attacks. Thus, the proposed scheme improves the existing pattern lock scheme. In our scheme, pattern is recorded by touch screen, however, it is different with existing schemes because of the layered pattern. During the pattern registration process, users register their own pattern with many layers. Thus, registered pattern is 3D shape. When the smudge attack is occurring, the attacker can see the shape of user pattern through the smudge on smartphone screen. However, it is described on 2D surface, so acquired pattern is not fully determine to users original 3D shape. Therefore, our scheme is resistant to social engineering attack, especially smudge attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.233-240
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• 2017

Fingerprint authentication identifies individuals based on user specific information. It is widely used as it is convenient, secure and has no risk of leakage, loss, or forgotten. However, the latent fingerprints remaining on the smart device's surface are vulnerable to smudge attacks. We analyze the usage patterns of individuals using smart device and propose methods to reconstruct damaged fingerprint images using fingerprint smudges. We examine the feasibility of smudge attacks with frequent usage situations by reconstructing fingerprint smudges collected from touch screens. Finally, we empirically verify the vulnerability of fingerprint authentication systems by showing high attack rates.

• Journal of Korea Multimedia Society
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• v.23 no.6
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• pp.738-746
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• 2020

In this paper, we propose an indirect PIN entry method that provides enhanced security against smudge, recording, and thermal attacks. Conventional mobile PIN entry methods use on-screen numeric keypad for both use of display and entry. Thus These methods are vulnerable to aforementioned attacks. In our method, passcode is same as that of the conventional PIN entry methods, and that is user-friendly way for mobile device users. Therefore, our method does not reduce user convenience which is one of the advantages of the conventional methods. In addition, our method is not a method of directly touching the on-screen numeric keypad for entering passcode like the conventional PIN methods. Unlike the conventional methods, our method uses an indirect passcode entry method that applied a passcode indicating key. According to the performance comparison result, proposed method provides user convenience similar to the conventional methods, and also provides a higher level of security and safety against recording, smudge, and thermal attacks than the conventional methods.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.117-123
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• 2023

In the fintech environment, Smart phones are mainly used for various service. User authentication technology is required to use safe services. Authentication is performed by transmitting authentication information to the server when the PIN or password is entered and touch the button completing authentication. But A post-attack is possible because the smudge which is the trace of using screen remains instead of recording attack with a camera or SSA(Shoulder Surfing Attack). To prevent smudge attacks, users must erase their fingerprints after authentication. In this study, we proposed a technique to determine whether to erase fingerprints. The proposed method performed erasing fingerprint which is the trace of touching after entering PIN and designed the security keypads that processes instead of entering completion button automatically when determined whether the fingerprint has been erased or not. This method suggests action that must erase the fingerprint when entering password. By this method, A user must erase the fingerprint to complete service request and can block smudge attack.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.119-125
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• 2015

In this paper, we propose a user friendly password input method for mobile devices which is secure against SSA. The proposed method is a numeric password input method such as a conventional PIN method. One of the buttons, numbers and colors, so as to display the two pieces of information to double. The user can select one of the colors or numbers within one button to type in the password. Because an attacker does not know whether the user has entered any color and number, the proposed technique is safe from the SSA. Also to be secure for smudge attacks and password guessing attacks through random changes in the number and color information.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.23-35
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• 2015

When people stands near someone's mobile device, it can easily be seen by others. To rephrase this, attackers use human psychology to earn personal information or credit information or other. People are exposed by social engineering attacks. It is certain that we need more than just recommendation for the security to avoid social engineering attacks. This is why I proposed this paper. In this paper, I proposed an authentication technique using NFC and Hash function to stand against social engineering attack. Proposed technique result is showing that it could prevent shoulder surfing, touch event information, spyware attack using screen capture and smudge attack which relies on detecting the oily smudges left behind by user's fingers. Besides smart phone, IPad, Galaxy tab, Galaxy note and more mobile devices has released and releasing. And also, these mobile devices usage rate is increasing widely. We need to attend these matters and study in depth.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4560-4575
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• 2018

Since smartphone contains various personal data, security is one of the important aspects in smartphone technologies. Up to now, various authentication techniques have been proposed to protect smartphones. The pattern lock on the Android system is one of the most widely used authentication methods for low-cost devices but it is known to be vulnerable to smudge attack or shoulder surfing attack. LG's smartphone uses its own technique, which is called "Knock Code." The knock code completes the authentication by touching the user defined area in turn on the screen. In this paper, we propose the new, enhanced version of knock code by adding the sliding operation and by using flexible area recognition. We conducted security analysis, which shows that under the same password size, the search space is overwhelmingly larger than the original algorithm. Also, by using the sliding operation, the proposed scheme shows resilience against smudge attacks. We implemented the prototype of our scheme. Experimental results show that compared with the original Knock Code and Android pattern lock, our scheme is more convenient while providing better security.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.915-922
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• 2017

The rapid increase in users of mobile smart devices has greatly expanded their range of activities. Compare to conventional mobile devices, smart devices have higher security requirements because they manage and use various kind of confidential information of the owners. However, the cation schemes provided by conventional smart devices are vulnerable to recent attacks such as shoulder surfing, recording, and smudge attacks, which are the social engineering attacks among the types of security attacks targeting the smart devices. In this paper, we propose a novel authentication method that is robust against social engineering attacks but sufficiently considering user's convenience. The proposed method is robust by using combination of a graphical authentication method and a text-based authentication method. Furthermore, our method is easier to memorize the password compare to the conventional graphical authentication methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.731-742
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• 2017

For all the various cryptographic techniques related to security, social technological attacks such as a shoulder surfing are infeasible to block off completely. Especially, the attacks are executed against financial facilities such as automated teller machine(ATM) which are located in public areas. Furthermore, online financial services whose rate of task management is consistently increasing are vulnerable to a shoulder surfing, smudge attacks, and key stroke inference attacks with google glass behind the convenience of ubiquitous business transactions. In this paper, we show that the security of ATM and internet banking can be reinforced against a shoulder surfing by using One-Time Keypad(OTK) and compare the security of OTK with those of ordinary keypad and One-Time Password(OTP).