notes

entropy.py

@@ -1,6 +1,12 @@
+#!/usr/bin/env python3
 import cv2
 import hashlib
 import secrets
+import time
+import argparse
+import sys
+
+sys.stdout.reconfigure(line_buffering=True)
 
 def fetch_frame_opencv(url):
     cap = cv2.VideoCapture(url)
@@ -10,18 +16,43 @@ def fetch_frame_opencv(url):
         raise ValueError("Failed to fetch frame.")
     return frame
 
-def generate_random_numbers(frame, bit_lengths=[16, 32, 64, 128, 256, 512, 1024, 2048, 4096):
+def generate_random_numbers(frame, bit_lengths):
     _, img_encoded = cv2.imencode('.jpg', frame)
     img_bytes = img_encoded.tobytes()
     entropy = hashlib.sha256(img_bytes).digest()
-    # Use secrets.randbits directly
     return {length: secrets.randbits(length) for length in bit_lengths}
 
-url = "http://192.168.0.200/mjpg/video.mjpg"
+def main():
+    parser = argparse.ArgumentParser(description="Generate random numbers from camera entropy.")
+    parser.add_argument("--url", default="http://192.168.0.200/mjpg/video.mjpg", help="Camera MJPEG stream URL")
+    parser.add_argument("--single", type=int, default=1, help="Generate N random numbers and exit (default: 1)")
+    parser.add_argument("--bit", type=int, default=256, help="Bit length of each random number (default: 256)")
+    parser.add_argument("--loop", action="store_true", help="Run forever, generating numbers every second")
+    args = parser.parse_args()
+
+    if args.loop:
+        while True:
             try:
-    frame = fetch_frame_opencv(url)
-    random_numbers = generate_random_numbers(frame)
-    for length, number in random_numbers.items():
-        print(f"{length}-bit random number: {hex(number)}")
+                frame = fetch_frame_opencv(args.url)
+                random_numbers = generate_random_numbers(frame, [args.bit])
+                for number in random_numbers.values():
+                    print(f"{number:x}")
             except Exception as e:
-    print(f"Error: {e}")
+                print(f"Error: {e}", file=sys.stderr)
+                time.sleep(1)  # Wait before retrying
+    else:
+        for i in range(args.single):
+            try:
+                frame = fetch_frame_opencv(args.url)
+                random_numbers = generate_random_numbers(frame, [args.bit])
+                for number in random_numbers.values():
+                    print(f"{number:x}")
+            except Exception as e:
+                print(f"Error: {e}", file=sys.stderr)
+                return 1
+            if args.single > 1 and i < args.single - 1:
+                time.sleep(1)  # Small delay between frames
+
+if __name__ == "__main__":
+    import sys
+    main()

notes.md

@@ -0,0 +1,10 @@
+# In order to use this there needs to be a IP webcam with some stream availabgle to use as the randomes generating source.
+# Sugest review code to see how it should be provided to the script. 
+#
+# generate entropy via pie fifo file. 
+python3 entropy.py --loop --bit 1024 | xxd -r > /tmp/entropy.fifo
+#
+# Use the generated entropy 
+sudo rngd -f -W 90% -x rdrand -x jitter -x pkcs11 -x rtlsdr -O namedpipe:path:/tmp/entropy.fifo -O namedpipe:timeout:2
+#
+#