Added code for practical-1.2, i.e. captcha image.

Codes/Code-1.2.py

@@ -0,0 +1,236 @@
+# CSDF - Practical-1 (Email Header Analysis)
+
+"""
+THIS CODE HAS BEEN TESTED AND IS FULLY OPERATIONAL.
+
+Problem Statement: CAPTCHA image - Implement a program to generate and verify CAPTCHA image.
+
+Code from CyberSecurityAndDigitalForensics (SPPU - Final Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-be-comp-content/CyberSecurityAndDigitalForensics
+"""
+
+# BEGINNING OF CODE
+import random
+import string
+from captcha.image import ImageCaptcha
+from PIL import Image
+import hashlib
+import time
+import os
+
+class CaptchaManager:
+    """
+    A comprehensive CAPTCHA generation and verification system
+    """
+    
+    def __init__(self, length=6, width=280, height=90):
+        """
+        Initialize the CAPTCHA manager
+        
+        Args:
+            length: Number of characters in CAPTCHA
+            width: Image width in pixels
+            height: Image height in pixels
+        """
+        self.length = length
+        self.image_captcha = ImageCaptcha(width=width, height=height)
+        self.captcha_store = {}  # Store CAPTCHA with expiry time
+        self.expiry_time = 180  # 3 minutes in seconds
+        
+    def generate_captcha_text(self):
+        """
+        Generate random CAPTCHA text
+        
+        Returns:
+            String of random alphanumeric characters
+        """
+        characters = string.ascii_uppercase + string.digits
+        # Exclude ambiguous characters like 0, O, I, 1
+        characters = characters.replace('0', '').replace('O', '').replace('I', '').replace('1', '')
+        captcha_text = ''.join(random.choice(characters) for _ in range(self.length))
+        return captcha_text
+    
+    def generate_captcha_image(self, captcha_text=None, filename='captcha.png'):
+        """
+        Generate CAPTCHA image
+        
+        Args:
+            captcha_text: Text to display (auto-generated if None)
+            filename: Output filename
+            
+        Returns:
+            Tuple of (captcha_text, session_id, filename)
+        """
+        if captcha_text is None:
+            captcha_text = self.generate_captcha_text()
+        
+        # Generate image
+        data = self.image_captcha.generate(captcha_text)
+        self.image_captcha.write(captcha_text, filename)
+        
+        # Create session ID
+        session_id = hashlib.md5(
+            f"{captcha_text}{time.time()}".encode()
+        ).hexdigest()
+        
+        # Store CAPTCHA with expiry time
+        self.captcha_store[session_id] = {
+            'text': captcha_text,
+            'timestamp': time.time()
+        }
+        
+        return captcha_text, session_id, filename
+    
+    def verify_captcha(self, session_id, user_input):
+        """
+        Verify user's CAPTCHA input
+        
+        Args:
+            session_id: Unique session identifier
+            user_input: User's input text
+            
+        Returns:
+            Dictionary with verification result
+        """
+        # Check if session exists
+        if session_id not in self.captcha_store:
+            return {
+                'success': False,
+                'message': 'Invalid session or CAPTCHA expired'
+            }
+        
+        captcha_data = self.captcha_store[session_id]
+        current_time = time.time()
+        
+        # Check expiry
+        if current_time - captcha_data['timestamp'] > self.expiry_time:
+            del self.captcha_store[session_id]
+            return {
+                'success': False,
+                'message': 'CAPTCHA expired. Please try again.'
+            }
+        
+        # Verify CAPTCHA (case-insensitive)
+        if user_input.upper() == captcha_data['text'].upper():
+            del self.captcha_store[session_id]  # Remove after successful verification
+            return {
+                'success': True,
+                'message': 'CAPTCHA verified successfully!'
+            }
+        else:
+            return {
+                'success': False,
+                'message': 'Incorrect CAPTCHA. Please try again.'
+            }
+    
+    def cleanup_expired(self):
+        """
+        Remove expired CAPTCHAs from storage
+        """
+        current_time = time.time()
+        expired_sessions = [
+            sid for sid, data in self.captcha_store.items()
+            if current_time - data['timestamp'] > self.expiry_time
+        ]
+        for sid in expired_sessions:
+            del self.captcha_store[sid]
+
+
+# Alternative simple implementation using Pillow
+class SimpleCaptcha:
+    """
+    Simple CAPTCHA implementation using Pillow
+    """
+    
+    @staticmethod
+    def generate(length=6):
+        """
+        Generate simple CAPTCHA with noise
+        
+        Returns:
+            Tuple of (captcha_text, Image object)
+        """
+        from PIL import ImageDraw, ImageFont
+        
+        # Generate random text
+        chars = ''.join(random.choice(string.ascii_uppercase + string.digits) 
+                       for _ in range(length))
+        
+        # Create image
+        img = Image.new('RGB', (200, 100), color=(73, 109, 137))
+        draw = ImageDraw.Draw(img)
+        
+        # Try to load a font, fallback to default if not available
+        try:
+            font = ImageFont.truetype('arial.ttf', 36)
+        except:
+            font = ImageFont.load_default()
+        
+        # Draw characters with random positions
+        x = 20
+        for char in chars:
+            y = random.randint(25, 35)
+            draw.text((x, y), char, font=font, fill=(255, 255, 0))
+            x += 30
+        
+        # Add noise (dots)
+        for _ in range(150):
+            x = random.randint(0, 200)
+            y = random.randint(0, 100)
+            draw.point((x, y), fill=(random.randint(0, 255), 
+                                    random.randint(0, 255), 
+                                    random.randint(0, 255)))
+        
+        # Add lines for distortion
+        for _ in range(5):
+            start = (random.randint(0, 200), random.randint(0, 100))
+            end = (random.randint(0, 200), random.randint(0, 100))
+            draw.line([start, end], fill=(255, 255, 255), width=1)
+        
+        return chars, img
+
+
+# Example usage and testing
+def main():
+    """
+    Demonstration of CAPTCHA generation and verification
+    """
+    print("=== CAPTCHA Generation and Verification Demo ===\n")
+    
+    # Initialize CAPTCHA manager
+    manager = CaptchaManager(length=6)
+    
+    # Generate CAPTCHA
+    captcha_text, session_id, filename = manager.generate_captcha_image()
+    print(f"CAPTCHA Generated: {captcha_text}")
+    print(f"Session ID: {session_id}")
+    print(f"Image saved as: {filename}\n")
+    
+    # Simulate user input
+    print("Verification Tests:")
+    
+    # Test 1: Correct input
+    result = manager.verify_captcha(session_id, captcha_text)
+    print(f"Test 1 (Correct): {result}")
+    
+    # Generate new CAPTCHA for next test
+    captcha_text, session_id, _ = manager.generate_captcha_image('test_captcha_2.png')
+    
+    # Test 2: Incorrect input
+    result = manager.verify_captcha(session_id, "WRONG")
+    print(f"Test 2 (Incorrect): {result}")
+    
+    # Test 3: Invalid session
+    result = manager.verify_captcha("invalid_session", "TEST")
+    print(f"Test 3 (Invalid Session): {result}")
+    
+    # Demonstrate simple CAPTCHA
+    print("\n=== Simple CAPTCHA Demo ===")
+    captcha_text, img = SimpleCaptcha.generate()
+    img.save('simple_captcha.png')
+    print(f"Simple CAPTCHA Text: {captcha_text}")
+    print("Image saved as: simple_captcha.png")
+
+
+if __name__ == "__main__":
+    main()
+# END OF CODE