CalculateEntropy

Calculates the entropy for the given data.

Type

python

Pack

CommonScripts

Source

import math
import string

import demistomock as demisto
from CommonServerPython import *  # noqa: E402 lgtm [py/polluting-import]

from CommonServerUserPython import *  # noqa: E402 lgtm [py/polluting-import]


def calculate_shannon_entropy(data, minimum_entropy):
    """Algorithm to determine the randomness of a given data.
    Higher is more random/complex, most English words will yield in average result of 3
    Args:
        data (str): The data to calculate entropy on.
        minimum_entropy (float): The minimum entropy.
    Returns:
        (str, dict, dict). Human readable, context, raw response
    """
    entropy = 0.0
    # each unicode code representation of all characters which are considered printable
    for char in (ord(c) for c in string.printable):
        # probability of event X
        p_x = float(data.count(chr(char))) / len(data)
        if p_x > 0:
            entropy += -p_x * math.log2(p_x)
    if entropy >= minimum_entropy:
        human_readable = tableToMarkdown(
            "Entropy results", {"Checked Value": data, "Entropy": entropy}, headers=["Checked Value", "Entropy"]
        )

        return human_readable, {"EntropyResult": {"checked_value": data, "entropy": entropy}}, {}

    return f"Entropy for {data} is {entropy} - lower than {minimum_entropy}", {}, {}


def main():
    try:
        data = demisto.args().get("data", "")
        minimum_entropy = float(demisto.args().get("minimum_entropy", 0))

        return_outputs(*calculate_shannon_entropy(data, minimum_entropy))
    except Exception as ex:
        return_error(f"Failed to execute calculate entropy script. Error: {ex!s}")


if __name__ in ("__main__", "__builtin__", "builtins"):
    main()

README

{
    "EntropyResult": {
        "checked_value": "abcd",
        "entropy": 2
    }
}