New drones can listen to underwater communication.

"Researchers from Princeton and MIT developed a way to intercept underwater messages from the air using radar, overturning long held assumptions about the security of underwater transmissions. Credit: Princeton University/Office of Engineering Communications" (ScitechDaily, Not So Secure: Drones Can Now Listen to Underwater Messages)

"Cross-medium eavesdropping technology challenges long-held assumptions about the security of underwater communications." (ScitechDaily, Not So Secure: Drones Can Now Listen to Underwater Messages)

"Researchers from Princeton and MIT have developed a method to intercept underwater communications from the air, challenging long-standing beliefs about the security of underwater transmissions." (ScitechDaily, Not So Secure: Drones Can Now Listen to Underwater Messages)

"The team created a device that uses radar to eavesdrop on underwater acoustic signals, or sonar, by decoding the tiny vibrations those signals produce on the water’s surface. In principle, the technique could also roughly identify the location of an underwater transmitter, the researchers said." (ScitechDaily, Not So Secure: Drones Can Now Listen to Underwater Messages)

New MIT drones can use radars to see submarines. They can hear the underwater messages. Submarines are used to communicate with each other. Drones can also connect themselves to the submarine's hull. They can slip into the harbor and then connect themselves to submarines. 

Those drones can hear everything inside the submarine. This is why submarines should have a vacuum layer between the inner and outer hulls. That vacuum layer makes it harder to hear things. That the crew says in the submarine. That vacuum can also decrease the noise from its engines. 

Drones can endanger privacy in many ways. They can take images of buildings. They can hear what people say in their rooms. They can carry normal and laser microphones in the houses. They can see through clothes using IR cameras. Drones can also put sensors on the data cables they can take images on screens. Drones can carry plasma- and spectroscopic sensors that allow them to see things like chemical compounds of the fuel, by analyzing exhaust gas.

By shooting targets using low-power laser systems, the plasma sensor sees the chemical compounds of the materials. So those drones can see many things. That humans cannot see.

But drones can also hear underwater communication. They can use acoustic microphones (hydrophones) to hear things. Like acoustic messages from submarines. Those systems can also hear sounds from the submarine engines and propellers. There is a possibility that the underwater drone travels near the submarine and connects itself to the submarine's hull. That allows those drones to hear everything that people say in the submarine. New drones can operate airborne and underwater. And they can operate in many ways against the enemy. 

Advanced acoustic detectors can also use laser beams and radar systems to see how water molecules move. Those miniaturized systems can perform almost the same missions as manned helicopters. 

The underwater drone can also use things like hollow warhead detonators to damage the submarine's outer shell. Those small drones can make holes in the hull like torpedo tube hatches. And they can damage submarine communication masts. Drones can also have acoustic transmitters that uncover the submarine's positions. 

 https://scitechdaily.com/not-so-secure-drones-can-now-listen-to-underwater-messages/