Recently, the people often face the problem of information leakage. They propose a leakage detection system which is independent of a database. This system focuses on the leakage caused by human action and malware. In an existing research, researchers calculate an edit distance between the last HTTP request and the new HTTP request. The edit distance is much smaller than the number of characters because a lot of HTTP requests have common characters. They can detect leakage easily because the information which is sent repeatedly is disregarded and the new information which is sent suddenly is digitized and its value stands out.