• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.266-277
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• 2020

As users' convenience increases, the issue of personal information leakage about smartphones is also becoming serious. Since all of the user's personal information needed to provide functions such as electronic banking services and personal file storage is stored in the smartphone, the user's important personal information may be exposed if the smartphone is lost or stolen. In order to protect this privacy, governments and telecommunications companies offer smartphone locking or initialization services, but there are many loopholes and problems. In this paper, we design and implement applications that prevent malicious use of a user's personal information stored on a smartphone when a smartphone is lost or stolen, and that automatically initializes the smartphone used after removing or altering the USIM chip and destroys the user's personal information stored within the phone. The proposed application prevents users from maliciously using their personal information when a smartphone is lost or stolen.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.67-75
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• 2003

The development of mobile phone is growing fast in the all over the world. Besides the basic voice communication, many multimedia services and global roaming service are capable in the 3rd generation mobile telecommunication. Because mobile phone has been the essential tool to communicate, the protection of privacy and the safe transmission are critical ones. In synchronous, asynchronous mode IMT2000 service, the mechanism of mutual authentication and generation of cipher key and integrity key are implemented in smart card chip called UIM, USIM. In this paper, we describe the authentication mechanism of 3GPP and 3CPP2 and its implementation results. Then, we specify a few problems which are not defined in standard.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.