66 lines
2.1 KiB
Python
66 lines
2.1 KiB
Python
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import sys
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import os
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from PIL import Image
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def encode_lsb(image_path, payload_path, output_path):
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print(f"[*] Encoding {payload_path} into {image_path}...")
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# 1. Read Payload
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with open(payload_path, 'rb') as f:
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payload_bytes = f.read()
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# Inject header to denote length of the file (8 bytes / 64 bits)
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payload_length = len(payload_bytes)
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header = payload_length.to_bytes(8, byteorder='big')
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full_payload = header + payload_bytes
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# Convert to binary string
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binary_payload = ''.join([format(b, '08b') for b in full_payload])
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payload_len_bits = len(binary_payload)
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print(f"[*] Payload is {payload_length} bytes ({payload_len_bits} bits).")
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# 2. Open Image
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img = Image.open(image_path)
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img = img.convert('RGB')
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pixels = img.load()
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width, height = img.size
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max_bits = width * height * 3
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if payload_len_bits > max_bits:
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raise ValueError(f"Payload too large! Need {payload_len_bits} bits, but image can only hold {max_bits} bits.")
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# 3. Inject Data via LSB
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bit_idx = 0
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for y in range(height):
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for x in range(width):
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if bit_idx >= payload_len_bits:
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break
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r, g, b = pixels[x, y]
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if bit_idx < payload_len_bits:
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r = (r & ~1) | int(binary_payload[bit_idx])
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bit_idx += 1
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if bit_idx < payload_len_bits:
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g = (g & ~1) | int(binary_payload[bit_idx])
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bit_idx += 1
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if bit_idx < payload_len_bits:
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b = (b & ~1) | int(binary_payload[bit_idx])
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bit_idx += 1
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pixels[x, y] = (r, g, b)
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if bit_idx >= payload_len_bits:
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break
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# 4. Save
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img.save(output_path, format="PNG")
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print(f"[+] Successfully saved encoded carrier to {output_path}")
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if __name__ == "__main__":
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if len(sys.argv) != 4:
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print("Usage: python3 stego_encoder.py <payload.tar.gz> <carrier.png> <output.png>")
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sys.exit(1)
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encode_lsb(sys.argv[2], sys.argv[1], sys.argv[3])
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