import math
from credsweeper.common.constants import Chars
from credsweeper.config import Config
from credsweeper.credentials import LineData
from credsweeper.file_handler.analysis_target import AnalysisTarget
from credsweeper.filters import Filter
from credsweeper.utils import Util
[docs]class ValueEntropyBase36Check(Filter):
"""Check that candidate have Shanon Entropy (for [a-z0-9])"""
def __init__(self, config: Config = None) -> None:
pass
[docs] @staticmethod
def get_min_data_entropy(x: int) -> float:
"""Returns minimal entropy for size of random data. Precalculated data is applied for speedup"""
if 15 == x:
y = 3.43
elif 24 == x:
y = 3.91
elif 25 == x:
y = 3.95
elif 10 <= x:
# approximation does not exceed standard deviation
y = 0.7 * math.log2(x) + 0.7
else:
y = 0
return y
[docs] def run(self, line_data: LineData, target: AnalysisTarget) -> bool:
"""Run filter checks on received credential candidate data 'line_data'.
Args:
line_data: credential candidate data
target: multiline target from which line data was obtained
Return:
True, if need to filter candidate and False if left
"""
entropy = Util.get_shannon_entropy(line_data.value, Chars.BASE36_CHARS.value)
min_entropy = ValueEntropyBase36Check.get_min_data_entropy(len(line_data.value))
return min_entropy > entropy or 0 == min_entropy