Editing Passive attack

{{Short description|Attempting to break a system solely based upon ciphertext}}
A '''passive attack''' on a [[cryptosystem]] is one in which the cryptanalyst cannot interact with any of the parties involved, attempting to break the system solely based upon observed data (i.e. the [[ciphertext]]).<ref name="geeks"/><ref name="book1"/> This can also include [[known plaintext attack]]s where both the [[plaintext]] and its corresponding ciphertext are known.

While active attackers can interact with the parties by sending data, a passive attacker is limited to intercepting communications (eavesdropping), and seeks to decrypt data by interpreting the transcripts of authentication sessions.<ref name="nlhb"/><ref name="manets"/> Since passive attackers do not introduce data of their own, they can be difficult to detect.<ref name="meshnets"/>

While most classical ciphers are vulnerable to this form of attack, most modern ciphers are designed to prevent this type of attack above all others.

== Attributes ==
*Traffic analysis
*Non-evasive [[eavesdropping]] and monitoring of transmissions<ref name="smashing"/>
*Because data unaffected, tricky to detect
*Emphasis on prevention ([[encryption]]) not detection
*Sometimes referred to as "tapping"

The main types of passive attacks are traffic analysis and release of message contents.

During a traffic analysis attack, the eavesdropper analyzes the traffic, determines the location, identifies communicating hosts and observes the frequency and length of exchanged messages. He uses all this information to predict the nature of communication. All incoming and outgoing traffic of the network is analyzed, but not altered.

For a release of message content, a telephonic conversation, an E-mail message or a transferred file may contain confidential data. A passive attack monitors the contents of the transmitted data.

Passive attacks are very difficult to detect because they do not involve any alteration of the data. When the messages are exchanged neither the sender nor the receiver is aware that a third party may capture the messages. This can be prevented by encryption of data.

A recent study on the cybersecurity of wearable devices used passive attacks on different smartwatches to test whether they have significant vulnerabilities and whether they are the best targets during the pairing process.<ref>{{Cite journal |last1=Silva-Trujillo |first1=Alejandra Guadalupe |last2=González González |first2=Mauricio Jacobo |last3=Rocha Pérez |first3=Luis Pablo |last4=García Villalba |first4=Luis Javier |date=January 2023 |title=Cybersecurity Analysis of Wearable Devices: Smartwatches Passive Attack |journal=Sensors |language=en |volume=23 |issue=12 |pages=5438 |doi=10.3390/s23125438 |issn=1424-8220 |pmc=10301545 |pmid=37420605 |bibcode=2023Senso..23.5438S |doi-access=free }}</ref>

==See also==
*[[Cybersecurity]]
*[[Known plaintext attack]]
*[[Chosen plaintext attack]]
*[[Chosen ciphertext attack]]
*[[Adaptive chosen ciphertext attack]]
*[[Topics in cryptography]]

==References==
<references>
<ref name="geeks">{{Cite web
  | url   = https://www.geeksforgeeks.org/active-and-passive-attacks-in-information-security/
  | title = Active and Passive attacks in Information Security
  | date  = September 5, 2018
  }}</ref>
<ref name="smashing">{{Cite book
  | chapter-url          = https://link.springer.com/chapter/10.1007/978-3-662-43933-3_9
  | chapter        = Smashing WEP in a Passive Attack
  | first1       = Pouyan
  | last1        = Sepehrdad
  | first2       = Petr
  | last2        = Sušil
  | first3       = Serge
  | last3        = Vaudenay
  | first4       = Martin
  | last4        = Vuagnoux
  | title = Fast Software Encryption
 | series = Lecture Notes in Computer Science
 | editor-first = Shiho
  | editor-last  = Moriai
  | date         = April 14, 2014
  | volume = 8424
 | publisher    = Springer
  | pages        = 155–178
  | via          = Springer Link
  | doi          = 10.1007/978-3-662-43933-3_9
  | isbn = 978-3-662-43932-6
 | s2cid = 10939507
 | url = http://infoscience.epfl.ch/record/186876
 }}</ref>
<ref name="book1">{{cite web
  | url   = http://vig.prenhall.com/catalog/academic/product/0,1144,0131873164,00.html
  | title = Cryptography and Network Security
  | last  = Stallings
  | first = William
  }}</ref>
<ref name="nlhb">{{cite book
  | chapter-url       = https://ieeexplore.ieee.org/document/5703571
  | chapter     = On the Security of Non-Linear HB (NLHB) Protocol against Passive Attack
  | last      = Abyaneh
  | first     = Mohammad Reza Sohizadeh
  | title = 2010 IEEE/IFIP International Conference on Embedded and Ubiquitous Computing
 | date      = December 2010
  | pages = 523–528
 | publisher = IEEE
  | doi = 10.1109/EUC.2010.86
 | arxiv = 1007.4414
 | isbn = 978-1-4244-9719-5
 | s2cid = 1043247
 }}</ref>
<ref name="manets">{{cite journal
  | url       = https://ieeexplore.ieee.org/document/6034725
  | title     = Secrecy Throughput of MANETs Under Passive and Active Attacks
  | last1     = Liang
  | first1    = Yingbin
  | last2     = Poor
  | first2    = H. Vincent
  | last3     = Ying
  | first3    = Lei
  | journal = IEEE Transactions on Information Theory
 | date      = October 2011
  | volume = 57
 | issue = 10
 | pages = 6692–6702
 | publisher = IEEE
  | doi = 10.1109/TIT.2011.2165800
 | s2cid = 15255934
 | url-access= subscription
  }}</ref>
<ref name="meshnets">{{Cite journal
  | url    = http://bura.brunel.ac.uk/handle/2438/3663
  | title  = Passive security threats and consequences in IEEE 802.11 wireless mesh networks
  | first1 = S.
  | last1  = Khan
  | first2 = N.
  | last2  = Mast
  | first3 = K. K.
  | last3  = Loo
  | first4 = A.
  | last4  = Silahuddin
  | date   = April 14, 2008
  | via    = bura.brunel.ac.uk
  }}</ref>
</references>

==Further reading==
*[http://vig.prenhall.com/catalog/academic/product/0,1144,0131873164,00.html Cryptography and Network Security] By [[William Stallings]]

[[Category:Cryptographic attacks]]


{{crypto-stub}}