eSecurity Planet: Software & Internet Security Trends, Virus Alerts

November 24, 2009

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cryptanalysis

Last modified: Monday, October 27, 2003

The study of a cryptographic system for the purpose of finding weaknesses in the system and breaking the code used to encrypt the data without knowing the code’s key. There are 4 basic steps in a typical cryptanalysis:

Determine the language being used
Determine the system being used – this can be a time-consuming stage in the process and involves counting character frequency, searching for repeated patterns and performing statistical tests.
Reconstruct the system’s specific keys
Reconstruction of the plain text – this step typically takes place at the same time as the keys are reconstructed.

Cryptanalysis often is used by governments in military and diplomatic surveillance, by enterprises in testing the strength of security procedures, and by malicious hackers in exploiting weaknesses in Web sites.