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Digital forensics exposing hidden computer data helps fight crime, scandals in Japan

An Aiforense Japan Data Recovery Institute Inc. worker places a hard drive in equipment for analysis on March 1, 2021, in Osaka's Kita Ward. (Mainichi/Saori Moriguchi)

OSAKA -- Digital forensics is becoming an increasingly important technique to restore and analyze data from confiscated computers and other devices in crime investigations in Japan.

    To learn how well the method is working, a Mainichi Shimbun reporter visited the first company in Japan that started restoring data through digital forensics. Aiforense Japan Data Recovery Institute Inc., based in Osaka's Kita Ward, has been undertaking data recovery from computers and other devices since it was founded in 1998. Its clients include investigative organizations and firms around the country.

    In a lab-like office in front of JR Osaka Station, hard drives and other information technology devices are lined up, and some special equipment to analyze data is also installed. When dealing with broken devices, workers wear special suits that cover their whole bodies to eliminate dust and static electricity.

    The company's founder and president Dai Shimogaito, 46, has analyzed some 7,000 devices and in 2018 acquired a patent related to a data-restoration technique. Despite comprising only six staff members, the company's technology has been highly evaluated, and work requests come one after another from around the country.

    Aiforense Japan Data Recovery Institute Inc. President Dai Shimogaito (Photo courtesy of the company)

    The firm receives a wide variety of job orders, including digital forensics for internal investigations of misconduct at companies and criminal probes, and for the recovery of data from broken electronic devices or those covered in mud due to disasters such as earthquakes and torrential rain. As it can take one to two years to analyze data in some cases, patience, on top of skill, is required.

    The Public Prosecutors Office set up digital forensic centers with expert staff in the Tokyo and Osaka district public prosecutors offices between 2017 and 2019. In the case of the Ministry of Finance's document doctoring scandal related to the heavily discounted sale of state land to school operator Moritomo Gakuen, they retrieved the ministry's original approval documents -- before they were tampered with -- by restoring deleted data in a computer submitted by the ministry. Furthermore, in a massive vote-buying scandal involving former Minister of Justice Katsuyuki Kawai and his wife Anri in connection with her victory in the 2019 House of Councillors election, a detailed list about distributed cash was recovered from Katsuyuki's computer that public prosecutors had confiscated. As these two recent cases show, digital forensics is becoming more widely used to retrieve strong evidence that was deleted.

    There have also been cases in which Aiforense Japan Data Recovery Institute's analysis significantly contributed to criminal probes. After receiving a request by an investigative organization, the company once restored the history of a web browser in a computer intentionally damaged. When Shimogaito reported the results after analyzing the data for more than half a year, an investigator thanked him, saying, "This history is what we wanted." The investigator cross-checked the web search history with security camera footage, and apparently confirmed the actions of an individual linked to a crime.

    "When our analysis results and information gathered by investigators are used together, they have major significance," Shimogaito said. "I think the need for data recovery will continue to rise in various situations."

    (Japanese original by Saori Moriguchi, Osaka City News Department)

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