Eavesdropping is the act of secretly or stealthily listening to the private conversation or communications of others without their consent in order to gather information.

Etymology

The verb ''eavesdrop'' is a back-formation from the noun ''eavesdropper'' ("a person who eavesdrops"), which was formed from the related noun ''eavesdrop'' ("the dripping of water from the

eaves The eaves are the edges of the roof which overhang the face of a wall and, normally, project beyond the side of a building. The eaves form an overhang to throw water clear of the walls and may be highly decorated as part of an architectural sty ...

of a house; the ground on which such water falls"). An eavesdropper was someone who would hang from the eave of a building so as to hear what is said within. The PBS documentaries ''Inside the Court of Henry VIII'' (April 8, 2015) and ''Secrets of Henry VIII’s Palace'' (June 30, 2013) include segments that display and discuss "eavedrops", carved wooden figures

Henry VIII Henry VIII (28 June 149128 January 1547) was King of England from 22 April 1509 until his death in 1547. Henry is known for his Wives of Henry VIII, six marriages and his efforts to have his first marriage (to Catherine of Aragon) annulled. ...

had built into the

(overhanging edges of the beams in the ceiling) of

Hampton Court Hampton Court Palace is a Listed building, Grade I listed royal palace in the London Borough of Richmond upon Thames, southwest and upstream of central London on the River Thames. Opened to the public, the palace is managed by Historic Royal ...

to discourage unwanted gossip or dissension from the King's wishes and rule, to foment paranoia and fear, and demonstrate that everything said there was being overheard; literally, that the walls had ears.

Techniques

Eavesdropping vectors include

telephone A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most ...

lines,

cellular network A cellular network or mobile network is a telecommunications network where the link to and from end nodes is wireless network, wireless and the network is distributed over land areas called ''cells'', each served by at least one fixed-locatio ...

email Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...

, and other methods of private instant messaging. Devices that support

VoIP Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as ...

and other communication software are also vulnerable to electronic eavesdropping by computer viruses categorized as trojan viruses or more broadly as

spyware Spyware (a portmanteau for spying software) is any malware that aims to gather information about a person or organization and send it to another entity in a way that harms the user by violating their privacy, endangering their device's securit ...

.Garner, p. 550

Network attacks

Network eavesdropping Network address translation, Network eavesdropping, also known as eavesdropping attack, sniffing attack, or IGMP snooping, snooping attack, is a method that retrieves user information through the internet. This attack happens on electronic devices ...

is a network layer attack that focuses on capturing small ''packets'' from the network transmitted by other computers and reading the data content in search of any type of information. This type of network attack is generally one of the most effective as a lack of

encryption In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the inf ...

services are used and when the connection between the two endpoints are weak and not secure. It is also linked to the collection of

metadata Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive ...

Security

There is a growing importance of security in communication systems, specifically in

wireless Wireless communication (or just wireless, when the context allows) is the transfer of information (''telecommunication'') between two or more points without the use of an electrical conductor, optical fiber or other continuous guided transm ...

technology. The need for security measures at different levels, including software encryption, hardware protection (e.g., trusted platform modules), and even the physical layer using wave-front engineering is as crucial than ever. Researchers have expressed the importance of addressing the privacy concerns from eavesdropping attacks because they impact the rights of users and the ability to have confidence in the devices as well as the entire

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

. Ensuring that users have trust and confidence in their Internet activities so users continue to engage actively in the system and share

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

References

External links