In May, a ransomware attack on Colonial Pipeline Co., the operator of the largest petroleum pipeline in the United States, forced the company to shut down its entire fuel supply network for five days, creating a serious impact on social and economic activities in the U.S. East Coast.

According to an annual report on 10 major information-related security threats issued by the Information-technology Promotion Agency, Japan in February, ransomware has now become the greatest threat to the information security of both the government and the private sector.

What makes this threat even more serious is the fact that it is targeted at key infrastructure that supports people’s lives and economic activities.