IDS::Algorithm::Chi2ICD - learn or test the character distribution of a string, using the Chi2 of ICD developed by Kruegel and Vigna (See the "SEE ALSO" section for the reference).


A usage synopsis would go here. Since it is not here, read on.

The learning and testing are based on section 4.2 in kruegel2003anomaly.


Someday more will be here.

ASSUMPTION: characters are 0..255; need to change to allow unicode, etc


Copyright 2005-2007, Kenneth Ingham. All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

Address bug reports and comments to: ids_test at When sending bug reports, please provide the versions of,,, the version of Perl, and the name and version of the operating system you are using. Since Kenneth is a PhD student, the speed of the reponse depends on how the research is proceeding.


Please report them.


IDS::Test, IDS::DataSource, IDS::Algorithm

"Anomaly detection of web-based attacks" by Christopher Kruegel and Giovanni Vigna, published in Proceedings of the 10th ACM conference on Computer and communications security 2003, pages 251--261,