Electronic Warfare (電子戦, Denshi-sen)(EW for short) is when the owner(s) of a computer system attempt to take over another computer system electronically while defending their control over their own. It is often utilised during ship-to-ship combat.
The primary goal of electronic warfare is to gain control of the opponent's systems. By seizing control of a ship's systems, one effectively seizes control of the ship. Even if one doesn't have completely control, gaining minor control can be used to gain an advantage in battle, like altering enemy targeting coordinates to prevent shots from hitting their target  or jamming their communications and radar.
In electronic warfare, there are two forms of action that can be taken - electronic attacks (電子攻撃, Denshi Kōgeki) which are aimed at seizing the enemy's systems, and electronic defences (電子防衛, Denshi Bōei) or electronic countermeasures (ECM for short) which are focused on protecting one's own systems from enemy attack.
In order to carry out electronic warfare, it is necessary to form a connection to the target systems. This means that the target is also capable of launching an electronic attack in retaliation, providing that they notice the initial electronic attack. It is possible to carry out an electronic attack without being detected, often by hiding the attacks within the normal patterns of signals, though care has to be taken for such an attack .
Certain systems are capable of automatically performing electronic warfare and fighting off electronic attacks , however they usually follow a pattern and if the opponent works out the pattern then they can overcome them .
An electronic attack can also be thwarted by either cutting a connection or shutting down the affected systems , however this carries its own set of risks, such as leaving a ship without its systems and vulnerable to attack in the middle of combat , or preventing access to other systems and networks.