diff --git a/stat/entropy.py b/stat/entropy.py
new file mode 100644
index 0000000..ac19a22
--- /dev/null
+++ b/stat/entropy.py
@@ -0,0 +1,180 @@
+# File: entropy.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import argparse
+from pathlib import Path
+
+import numpy as np
+import pandas as pd
+import plotly.graph_objects as go
+
+from utils.extractor import load_data
+
+
+def _to_int(x):
+ """Convert a hex string or integer to int, returning NaN on failure."""
+ if isinstance(x, (int, np.integer)):
+ return int(x)
+ if isinstance(x, str):
+ try:
+ return int(x, 16)
+ except ValueError:
+ return np.nan
+ return np.nan
+
+
+def calculate_byte_entropy(df: pd.DataFrame) -> pd.DataFrame:
+ """Calculates Shannon entropy per byte position for each identifier."""
+ byte_cols = [f"b{i}" for i in range(8)]
+ available_cols = [col for col in byte_cols if col in df.columns]
+ if not available_cols:
+ raise ValueError("No byte columns (b0-b7) found in the DataFrame")
+
+ df_bytes = df[available_cols].copy()
+ for col in available_cols:
+ df_bytes[col] = df_bytes[col].apply(_to_int)
+
+ def entropy(s: pd.Series) -> float:
+ s = s.dropna()
+ if s.empty:
+ return 0.0
+ p = s.value_counts(normalize=True)
+ return -np.sum(p * np.log2(p))
+
+ return df.groupby("Identifier")[available_cols].agg(entropy)
+
+
+def plot_entropy_heatmap(entropy_df: pd.DataFrame, title: str) -> go.Figure:
+ """Generates an interactive heatmap of byte-level Shannon entropy."""
+ x = entropy_df.columns.tolist()
+ y = entropy_df.index.tolist()
+ z = entropy_df.values
+
+ fig = go.Figure(
+ data=go.Heatmap(
+ z=z,
+ x=x,
+ y=y,
+ colorscale=[
+ [0.0, "#ffffff"],
+ [0.15, "#fff7ec"],
+ [0.35, "#fee8c8"],
+ [0.55, "#fdd49e"],
+ [0.75, "#fdbb84"],
+ [1.0, "#ef6548"],
+ ],
+ xgap=3,
+ ygap=3,
+ text=np.round(z, 2),
+ texttemplate="%{text}",
+ textfont={
+ "size": 11,
+ "color": "#2a2a2a",
+ "family": "Segoe UI, Arial, sans-serif",
+ },
+ hoverongaps=False,
+ hovertemplate=(
+ "%{y}
"
+ "Byte %{x}: %{z:.2f} bits"
+ ),
+ colorbar=dict(
+ title=dict(
+ text="Entropy (bits)",
+ side="top",
+ font=dict(size=13, color="#1a1a1a"),
+ ),
+ orientation="h",
+ thickness=15,
+ len=0.35,
+ x=1.0,
+ xanchor="right",
+ y=1.02,
+ yanchor="bottom",
+ tickfont=dict(size=11, color="#2a2a2a"),
+ tickformat=".1f",
+ outlinewidth=0.5,
+ outlinecolor="#cccccc",
+ ),
+ )
+ )
+
+ fig.update_layout(
+ title=dict(
+ text=title,
+ font=dict(size=20, color="#1a1a1a"),
+ x=0.5,
+ xanchor="center",
+ pad=dict(b=20),
+ ),
+ height=max(600, len(y) * 28 + 150),
+ autosize=True,
+ template="plotly_white",
+ xaxis=dict(
+ title=dict(text="Byte Position", font=dict(size=13, color="#1a1a1a")),
+ side="top",
+ dtick=1,
+ showgrid=False,
+ linecolor="#bdbdbd",
+ tickfont=dict(size=12, color="#2a2a2a"),
+ ticks="outside",
+ ticklen=4,
+ tickcolor="#cccccc",
+ ),
+ yaxis=dict(
+ title=dict(text="PGN or CAN ID", font=dict(size=13, color="#1a1a1a")),
+ autorange="reversed",
+ showgrid=False,
+ linecolor="#bdbdbd",
+ tickfont=dict(size=12, color="#2a2a2a"),
+ ticks="outside",
+ ticklen=4,
+ tickcolor="#cccccc",
+ automargin=True,
+ ),
+ font=dict(family="Segoe UI, Arial, sans-serif", size=12, color="#2a2a2a"),
+ hoverlabel=dict(
+ bgcolor="white",
+ font_size=13,
+ font_family="Segoe UI",
+ bordercolor="#cccccc",
+ ),
+ margin=dict(l=200, r=40, t=120, b=60),
+ )
+ return fig
+
+
+if __name__ == "__main__":
+ parser = argparse.ArgumentParser(
+ description="Analyze CAN bus byte-level entropy"
+ )
+ parser.add_argument(
+ "input", type=Path, help="Path to the input CAN log file"
+ )
+ parser.add_argument(
+ "output",
+ type=Path,
+ nargs="?",
+ default=Path("entropy_report.html"),
+ help="Path to the output HTML report",
+ )
+ parser.add_argument(
+ "title",
+ nargs="?",
+ default="CAN Bus Byte-Level Entropy",
+ help="Title for the HTML report",
+ )
+ args = parser.parse_args()
+
+ df = load_data(args.input)
+ entropy_df = calculate_byte_entropy(df)
+ fig = plot_entropy_heatmap(entropy_df, title=args.title)
+
+ config = {
+ "responsive": True,
+ "displaylogo": False,
+ "scrollZoom": True,
+ "modeBarButtonsToAdd": ["toggleSpikelines"],
+ "toImageButtonOptions": {"format": "png", "scale": 2},
+ }
+ fig.write_html(str(args.output), include_plotlyjs="cdn", config=config)