Shorten URL service is the method of using short URL instead of long URL, it redirect short url to long URL. While the users of microblog increased rapidly, as the creating and usage of shorten URL is convenient, shorten url became common under the limited length of writing on microblog. E-mail, SMS and books use shorten URL well, because of its simplicity. But, there is no relativeness between the most of shorten URLs and their target URLs, user can not expect the target URL. To cover this problem, there is attempts such as changing the shorten URL service name, inserting the information of website into shorten URL, and the usage of shortcode of physical address. However, each ones has the limits, so these are the trouble of automation, relatively long address, and the narrowness of applicable targets. SHRT is complementary to the attempts, as getting the idea from the writing system of Arabic. Though the writing system of Arabic has no vowel alphabet, Arabs have no difficult to understand their writing. This paper proposes SHRT, new method of URL Shortening. SHRT makes user guess the target URL using Relative word of the lowest domain of target URL without vowels.※ "본 연구는 미래창조과학부 및 정보통신산업진흥원의 대학 IT연구센터 지원사업의 연구결과로 수행되었음"

Portal site is not only providing search engine and e-mail service but also various services including blog, news, shopping, and others. The fact that average number of daily login for Korean portal site Naver is reaching 300 million suggests that many people are using portal sites. One of the most famous social network service, Facebook subscribers to reach 1.2 billion 30 million people at the time of the February 2014. With the increase in number of users followed by the diversity in types of services provided by portal sites and SNS, the attack is also increasing. Therefore, the objective of this study lies in analysing whole procedure of password authentication system of portal sites, SNS and analysing the security threat that may occur accordingly. Also, the security requirement corresponding to analysed security threat was extracted and the analysis on implementation of security requirements by portal sites and SNS was conducted.