The growth of mobile devices used in our daily lives can mean more than one type of digital forensic targets may exist. Unlike desktop computers and file servers, mobile devices are more often used in daily life and contain precise and detailed personal information. Accordingly, if a mobile device is confiscated and digital forensic procedures are conducted, various private information may be disclosed during the investigation process. Moreover, privacy exposure from the investigative agency is not the entire risk. For example, privacy exposure may occur when evidence is released outside the investigation agency or possibly when other case managers arbitrarily read the evidence. Additional risks may arise during storage process as well. Privacy is a fundamental right of the people protected by the Constitution. Thus, if under the confines of the law, infringement or privacy limitations are necessary then it should be done to the minimum extent possible. In this paper, we will study 1) the laws relating to digital forensic procedures in Korea, the United States, the E.U., 2) examine the types of private information that can be exposed through mobile devices, and 3) suggest passcode (which is a first-generation cryptography, based on authentication) and other encryption methods, more specifically public-key and isomorphic encryption to protect the privacy of mobile evidence.