feat: add rizzfield challenge

rizzfield/README.md

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+# Rizzfield
+
+## Text
+
+What's 9 + 10?
+
+## Files
+
+rizzfield.gif
+
+## How to Deploy
+
+N/A

rizzfield/SOLUTION.md

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+## Difficulty
+
+Medium++
+
+## Category
+
+Steg
+
+## How To Solve
+
+I changed the color of the 21th frame. What you can do, is randomize the entire palette of the 21th frame and the text should become visible.
+
+## Flag
+
+IGCTF{H3sGoTsTh3RiZz}

rizzfield/frame_destroyer.py

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+from PIL import Image
+import numpy as np
+
+# Load the GIF
+gif_path = "./garfield-garfield-meme-ezgif.com-added-text.gif"
+gif = Image.open(gif_path)
+
+# Define the color you want to replace (original text color) and the new color
+original_text_color = (55, 126, 34)  # Replace with the actual color of the text in RGB
+new_text_color = (255, 254, 253)           # Desired replacement color, e.g., black
+
+# Function to find the indices of the top 5 closest colors in the palette
+def find_closest_palette_color_indices(palette, target_color, num_colors=25):
+    palette = np.array(palette).reshape(-1, 3)
+    target_color = np.array(target_color)
+    distances = np.sqrt(((palette - target_color) ** 2).sum(axis=1))
+    # Get the indices of the closest colors
+    return distances.argsort()[:num_colors]
+
+# Extract frames and modify frame 21
+frames = []
+for i in range(gif.n_frames):
+    gif.seek(i)
+    new_frame = gif.convert("P", palette=Image.ADAPTIVE)  # Convert to palette mode
+    
+    if i == 20:
+        # Get the palette and find the closest color indices for the original text color
+        palette = new_frame.getpalette()
+        closest_color_indices = find_closest_palette_color_indices(palette, original_text_color, num_colors=255)
+        
+        # Modify the palette at each of the closest color indices to the new color
+        for idx in closest_color_indices:
+            palette[idx*3:idx*3+3] = list(new_text_color)
+        new_frame.putpalette(palette)
+
+    # Append the modified (or unmodified) frame
+    frames.append(new_frame)
+
+# Save the modified GIF
+output_path = "./modified_gif.gif"
+frames[0].save(output_path, save_all=True, append_images=frames[1:], loop=0, duration=gif.info['duration'])
+print(f"Modified GIF saved as {output_path}")

rizzfield/randomize_palette.py

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+from PIL import Image
+import random
+
+# Load the GIF
+gif_path = "./garfield-garfield-meme-ezgif.com-added-text.gif"
+gif = Image.open(gif_path)
+
+# Function to randomize the palette
+def randomize_palette(palette):
+    # Convert palette (a flat list) to a list of (R, G, B) tuples
+    colors = [(palette[i], palette[i + 1], palette[i + 2]) for i in range(0, len(palette), 3)]
+    # Shuffle the colors
+    random.shuffle(colors)
+    # Flatten the list back to the original format
+    randomized_palette = [val for color in colors for val in color]
+    return randomized_palette
+
+# Extract frames and modify frame 21
+frames = []
+for i in range(gif.n_frames):
+    gif.seek(i)
+    new_frame = gif.convert("P", palette=Image.ADAPTIVE)  # Convert to palette mode
+    
+    if i == 20:
+        # Get the palette of the frame and randomize it
+        palette = new_frame.getpalette()
+        randomized_palette = randomize_palette(palette)
+        # Apply the randomized palette to the frame
+        new_frame.putpalette(randomized_palette)
+
+    # Append the modified (or unmodified) frame
+    frames.append(new_frame)
+
+# Save the modified GIF
+output_path = "./randomized_palette_gif.gif"
+frames[0].save(output_path, save_all=True, append_images=frames[1:], loop=0, duration=gif.info['duration'])
+print(f"Modified GIF with randomized palette saved as {output_path}")