An eavesdropper (see also Shannon's model) is a person or party who tries to get unauthorized access to data, e.g. by breaking into a computer system or tapping into a communication channel. The use of a proper cryptosystem should make it impossible for the eavesdropper to determine the meaning of an intercepted message. Meaningful plaintext has been replaced by unintelligible\break ciphertext.
A common distinction is between passive eavesdroppers, who only read or listen to the ciphertext, and active eavesdroppers who may replace a ciphertext by another one, retransmit a ciphertext at a different moment, insert their own texts, etc.
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© 2005 International Federation for Information Processing
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Quisquater, JJ. (2005). Eavesdropper. In: van Tilborg, H.C.A. (eds) Encyclopedia of Cryptography and Security. Springer, Boston, MA . https://doi.org/10.1007/0-387-23483-7_118
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DOI: https://doi.org/10.1007/0-387-23483-7_118
Publisher Name: Springer, Boston, MA
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