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"Active Cyber Defense" Explained: Efforts to Prevent Cyberattacks and Limit Damage [Keyword of the Week]
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Japan has started a new cyber defense system called "active cyber defense." It lets the government spot and stop cyber attacks before they cause major damage to important services like power and banking.
What happened
On October 1, 2026, the main parts of Japan's new cyber defense law took effect. The law lets the government find signs of attacks early and act before serious harm happens. Two of the three parts started on this day. The third part, about using communication information, is planned to start in autumn 2027.
Why a new approach was needed
Until now, each organization protected its own systems with security software and firewalls. It then responded after an attack hit. But some attackers now hide inside systems of power, phone, train, and bank companies. If those services stop, many people could be hurt. So the government wants to see attacks coming and respond sooner.
Key facts
- The law was passed in May 2025 and follows a 2022 national security plan.
- Companies in 15 areas, such as electricity, gas, water, rail, telecom, and finance, are called "critical infrastructure operators."
- On October 1, 2026, a council of about 100 organizations was set up to share information between government and companies.
- The system has three parts: public-private cooperation, use of communication information, and access and disabling of attack tools.
How the three parts work
First, public-private cooperation means companies must report important system details and certain attacks. The government cleans out private details from threat information and shares it quickly. Second, communication information is studied to find servers used in attacks. Only machine data, like IP addresses, is used, not the content of emails. Third, police can enter an attacking computer over a network and stop the attack. For example, they can delete harmful programs or shut down a server. The Self-Defense Forces can also help with very serious attacks from abroad. The government says this is not revenge. It is meant to stop harm.
Why it matters
Power, phone, and bank services are part of daily life. If attackers stop them, the damage can be large and spread fast. This system aims to stop attacks before they spread. It also raises questions about privacy, since the law touches the secrecy of communications. The law sets limits, such as an independent committee that must approve some uses of communication data.