Index of Coincidence #1907
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Index of Coincidence #1907
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Updated for compatibility with YARA v4.3.2; tests passing as expected. |
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The index of coincidence "provides a measure of how likely it is to draw two matching letters by randomly selecting two letters from a given text" (reference: https://en.wikipedia.org/wiki/Index_of_coincidence).
As we know this index will be around
0.067for English text, this may be a useful indicator for plaintext strings. An example usage can be seen here: https://gchq.github.io/CyberChef/#recipe=Index_of_Coincidence()&input=VGhpcyBhIHRlc3QgZm9yIHRoZSBpbmRpY2F0b3Igb2YgY29pbmNpZGVuY2UI've added this function for both data offsets/string values to the
mathmodule. I've also added documentation and tests for it.