Keystroke dynamics refers to a way of typing a string of characters. Since one has his/her own typing behavior, one's keystroke dynamics can be used as a distinctive biometric feature for user authentication. In this paper, two authentication algorithms based on keystroke dynamics of long and free texts are proposed. The first is the K-S score, which is based on the Kolmogorov-Smirnov test, and the second is the 'R-A' measure, which combines 'R' and 'A' measures proposed by Gunetti and Picardi (2005). In order to verify the authentication performance of the proposed algorithms, we collected more than 3,000 key latencies from 34 subjects in Korean and 35 subjects in English. Compared with three benchmark algorithms, we found that the K-S score was outstanding when the reference and test key latencies were not sufficient, while the 'R-A' measure was the best when enough reference and test key latencies were provided. 이러한 패스워드 기반 사용자 인증 방법론의 약점을 극복하기 위하여 패스워드와 생체 기반 정보(biometrics)를 결합한 다양한 2차 인증 방법론들이 연구되었다 (Furnell and Clarke, 2005;Jain et al., 1999;Prabhakar et al., 2003;Yager and Dunstone, 2010). 생체 기반 정보는 그 형태에 따라서 지문, 홍채, 동공 등 개인이 유전 본 연구는 서울과학기술대학교 교내연구과제의 지원을 받아 수행되었습니다. †