Cardinals eavesdropping in the Vatican. A painting by Henri Adolphe Laissement [fr], 1895

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.


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 of a house; the ground on which such water falls").[1]

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)[2] and Secrets of Henry VIII’s Palace (June 30, 2013) include segments that display and discuss "eavedrops", carved wooden figures Henry VIII had built into the eaves (overhanging edges of the beams in the ceiling) of Hampton Court to discourage unwanted gossip or dissension from the King's wishes and rule, to foment paranoia and fear,[2] and demonstrate that everything said there was being overheard; literally, that the walls had ears.[3]


Eavesdropping vectors include telephone lines, cellular networks, email, and other methods of private instant messaging. Devices that support VoIP and other communication software are also vulnerable to electronic eavesdropping by computer viruses categorized as trojan viruses or more broadly as spyware.[4]

Network attacks

Network eavesdropping 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.[5] This type of network attack is generally one of the most effective as a lack of encryption services are used.[6] It is also linked to the collection of metadata.


There is a growing importance of security in communication systems, specifically in wireless 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.[7]

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. Ensuring that users have trust and confidence in their Internet activities so users continue to engage actively in the system and share data.[8]

See also


  1. ^ "eavesdrop – Definition of eavesdrop in English by Oxford Dictionaries". Oxford Dictionaries – English. Archived from the original on August 11, 2017. Retrieved September 10, 2023.
  2. ^ a b Inside the Court of Henry VIII. Public Broadcasting Service. April 8, 2016.
  3. ^ Stollznow, Karen (August 7, 2014). "Eavesdropping: etymology, meaning, and some creepy little statues". Archived from the original on July 28, 2018. Retrieved June 23, 2016.
  4. ^ Garner, p. 550[full citation needed]
  5. ^ "TeamMentor 3.5". Archived from the original on September 27, 2019. Retrieved September 27, 2019.
  6. ^ "What Are Eavesdropping Attacks?". Fortinet. Retrieved October 2, 2021.
  7. ^ Ma, Jianjun; Shrestha, Rabi; Adelberg, Jacob; Yeh, Chia-Yi; Hossain, Zahed; Knightly, Edward; Jornet, Josep Miquel; Mittleman, Daniel M. (November 2018). "Security and eavesdropping in terahertz wireless links". Nature. 563 (7729): 89–93. Bibcode:2018Natur.563...89M. doi:10.1038/s41586-018-0609-x. ISSN 1476-4687. PMID 30323288. S2CID 53085137.
  8. ^ "A Counter-Eavesdropping Technique for Optimized Privacy of Wireless Industrial IoT Communications". Retrieved February 9, 2024.