Minimize the memory footprint of sensitive data

src/PAN.py

@@ -1,3 +1,4 @@
+import gc
 import re
 
 
@@ -7,17 +8,26 @@ class PAN:
     brand: str
 
     __pan: str
+    __masked: str
 
     def __init__(self, brand: str, pan: str) -> None:
 
-        self.brand, self.__pan = brand, pan
+        self.brand = brand
+        self.__masked = self.__mask_pan(pan)
 
-    def get_masked_pan(self) -> str:
+        # Clear the PAN from memory ASAP
+        del pan
+        gc.collect()
+
+    def __mask_pan(self, pan: str) -> str:
         """The first six and last four digits are the maximum number of digits that may be displayed"""
-        standardized = self.__pan.replace(' ', '').replace('-', '')
-        pan_out: str = standardized[0:6] + \
+        standardized = pan.replace(' ', '').replace('-', '')
+        masked: str = standardized[0:6] + \
             re.sub(r'\d', '*', standardized[6:-4]) + standardized[-4:]
-        return f'{self.brand}:{pan_out}'
+        return masked
+
+    def get_masked_pan(self) -> str:
+        return f'{self.brand}:{self.__masked}'
 
     @staticmethod
     def is_valid_luhn_checksum(pan: str) -> bool:

src/PanFinder.py

@@ -1,3 +1,4 @@
+import gc
 from re import Pattern
 
 from config import PANHuntConfiguration
@@ -16,6 +17,9 @@ def find(self, text: str) -> list[PAN]:
             for pan in regex.findall(text):
                 if PAN.is_valid_luhn_checksum(pan=pan) and not config.is_excluded(pan=pan):
                     matches.append(PAN(brand=brand, pan=pan))
+                    # Clear the PAN from memory ASAP
+                    del pan
+                    gc.collect()
                     break
 
         return matches