From 5469c2563e40ffef33da2eb11852c5e8068e841d Mon Sep 17 00:00:00 2001
From: Pronoy Mandal <lukex9442@gmail.com>
Date: Thu, 27 Oct 2022 22:47:25 +0530
Subject: [PATCH] Update check_strong_password.py

1. Change the functional concept that a strong password checker must return a boolean indicating whether the password is strong or not AND not a response string, the choice of which can be subjective.
2. Add another alternative checker which has a theoretical time complexity better than the original one.
3. Rectify the length checking to adhere to the minimum length as opposed to a hardcoded value.
4. Optimise to make more Pythonic expressions and returns.
5. Add comments wherever necessary.
---
 other/check_strong_password.py | 81 +++++++++++++++++++++++++---------
 1 file changed, 61 insertions(+), 20 deletions(-)

diff --git a/other/check_strong_password.py b/other/check_strong_password.py
index 95bb327addf4..04766509870a 100644
--- a/other/check_strong_password.py
+++ b/other/check_strong_password.py
@@ -5,40 +5,81 @@
 from string import ascii_lowercase, ascii_uppercase, digits, punctuation
 
 
-def strong_password_detector(password: str, min_length: int = 8) -> str:
+def is_strong_password(password: str, min_length: int = 8) -> bool:
     """
-    >>> strong_password_detector('Hwea7$2!')
-    'This is a strong Password'
+    >>> is_strong_password('Hwea7$2!')
+    True
 
-    >>> strong_password_detector('Sh0r1')
-    'Your Password must be at least 8 characters long'
+    >>> is_strong_password('Sh0r1')
+    False
 
-    >>> strong_password_detector('Hello123')
-    'Password should contain UPPERCASE, lowercase, numbers, special characters'
+    >>> is_strong_password('Hello123')
+    False
 
-    >>> strong_password_detector('Hello1238udfhiaf038fajdvjjf!jaiuFhkqi1')
-    'This is a strong Password'
+    >>> is_strong_password('Hello1238udfhiaf038fajdvjjf!jaiuFhkqi1')
+    True
 
-    >>> strong_password_detector(0)
-    'Your Password must be at least 8 characters long'
+    >>> is_strong_password(0)
+    False
     """
 
-    if len(str(password)) < 8:
-        return "Your Password must be at least 8 characters long"
+    # Rudimentary check when an int or float type is used as a password
+    # having no. of digits less than min_length
+    if len(str(password)) < min_length:
+        return False
 
+    # Boolean character flags which are set on encountering a character of
+    # a given type
     upper = any(char in ascii_uppercase for char in password)
     lower = any(char in ascii_lowercase for char in password)
     num = any(char in digits for char in password)
     spec_char = any(char in punctuation for char in password)
 
-    if upper and lower and num and spec_char:
-        return "This is a strong Password"
+    return upper and lower and num and spec_char
 
-    else:
-        return (
-            "Password should contain UPPERCASE, lowercase, "
-            "numbers, special characters"
-        )
+
+def is_strong_password_2(password: str, min_length: int = 8) -> bool:
+    """
+    >>> is_strong_password_2('Hwea7$2!')
+    True
+
+    >>> is_strong_password_2('Sh0r1')
+    False
+
+    >>> is_strong_password_2('Hello123')
+    False
+
+    >>> is_strong_password_2('Hello1238udfhiaf038fajdvjjf!jaiuFhkqi1')
+    True
+
+    >>> is_strong_password_2(0)
+    False
+    """
+    # Initialise boolean flags which toggle when the first occurrence of a
+    # type is encountered
+    upper = lower = num = spec_char = False
+
+    # Rudimentary check when an int or float type is used as a password
+    # having no. of digits less than min_length
+    if len(str(password)) < min_length:
+        return False
+
+    # Parse each of the characters and check whether they are within the
+    # concerned lexicographic boundaries
+    # Toggle respective flags when you encounter a character type
+    # Avoid the check when the concerned character flag is already set
+
+    for char in password:
+        if not num and "0" <= char <= "9":
+            num = True
+        elif not upper and "A" <= char <= "Z":
+            upper = True
+        elif not lower and "a" <= char <= "z":
+            lower = True
+        elif not spec_char and char in punctuation:
+            spec_char = True
+
+    return num and spec_char and upper and lower
 
 
 if __name__ == "__main__":