130 lines
4.9 KiB
Python
130 lines
4.9 KiB
Python
import cv2
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import numpy as np
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class img_steg:
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def __init__(self, image_name: str = None, bit_to_hide: list[int] = None) -> None:
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"""
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Initialize the class
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:param image_name: Name of the image to encode or decode
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:type image_name: str
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:param bit_to_hide: List of bit position to hide the data (LSB is 1, MSB is 8) Default is LSB (index = 7)
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:type bit_to_hide: list[int]
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"""
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if image_name:
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self.image_name = image_name
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else:
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raise FileNotFoundError("[!] Please specify an image file")
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self.bit_to_hide = [8 - bit_pos for bit_pos in bit_to_hide] if bit_to_hide else [
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7] # Default is LSB (index = 7)
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self.delimiter = "abc-123-a=="
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def encode(self, secret_data: str = "Hello World") -> np.ndarray:
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"""
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Encode the secret data in the image
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:param secret_data: Data to hide in the image
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:type secret_data: str
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:return: Encoded Image
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:rtype: np.ndarray
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"""
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image = cv2.imread(self.image_name) # read image
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n_bits = (image.shape[0] * image.shape[1] * 3) * 8 * len(self.bit_to_hide) # Max bits to encode
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secret_data += self.delimiter # Add delimiter at the end of data
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if len(secret_data) * 8 > n_bits:
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raise ValueError("[!] Insufficient bytes, need a bigger image or less data")
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# Convert bit to hide position
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data_index = 0
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binary_secret_data = self.to_bin(secret_data) # Convert data to binary
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data_len = len(binary_secret_data) # size of data to hide
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for row in image:
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for pixel in row:
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r, g, b = self.to_bin(pixel) # Convert RGB Values to binary format
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for bit_pos in self.bit_to_hide:
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if data_index < data_len:
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r = list(r)
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r[bit_pos] = binary_secret_data[
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data_index] # hide data into specified bit position of red pixel
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pixel[0] = int(''.join(r), 2)
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data_index += 1
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if data_index < data_len:
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g = list(g)
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g[bit_pos] = binary_secret_data[
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data_index]
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pixel[1] = int(''.join(g), 2)
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data_index += 1
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if data_index < data_len:
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b = list(b)
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b[bit_pos] = binary_secret_data[
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data_index]
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pixel[2] = int(''.join(b), 2)
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data_index += 1
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if data_index >= data_len:
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break
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pixel[0] = int(''.join(r), 2) # convert modified binary back to integer for red pixel
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pixel[1] = int(''.join(g), 2) # convert modified binary back to integer for green pixel
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pixel[2] = int(''.join(b), 2) # convert modified binary back to integer for blue pixel
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if data_index >= data_len:
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break
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return image
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def decode(self) -> str:
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"""
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Decode the data hidden in the image
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:return: Decoded Data: String
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"""
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image = cv2.imread(self.image_name) # read image
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binary_data = ""
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for row in image:
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for pixel in row:
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r, g, b = self.to_bin(pixel)
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for bit_pos in self.bit_to_hide:
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binary_data += r[bit_pos] # retrieve data from specified bit position of red pixel
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binary_data += g[bit_pos] # retrieve data from specified bit position of green pixel
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binary_data += b[bit_pos] # retrieve data from specified bit position of blue pixel
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# Split by 8 bits
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all_bytes = [binary_data[i: i + 8] for i in range(0, len(binary_data), 8)]
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# Convert from bits to characters
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decoded_data = ""
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for byte in all_bytes:
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decoded_data += chr(int(byte, 2))
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if decoded_data[-len(self.delimiter):] == self.delimiter:
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break
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return decoded_data[:-len(self.delimiter)]
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def to_bin(self, data: str) -> str | list[str]:
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"""
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Convert data to binary format as string
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:param data: Data to convert
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:type data: str
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:return: Binary Data
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:rtype: str | list[str]
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"""
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if isinstance(data, str):
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return ''.join([format(ord(i), "08b") for i in data])
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elif isinstance(data, bytes) or isinstance(data, np.ndarray):
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return [format(i, "08b") for i in data]
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elif isinstance(data, int) or isinstance(data, np.unit8):
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return format(data, "08b")
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else:
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raise TypeError("Type not supported")
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def main():
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raise NotImplementedError("This module is not meant to run by itself")
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if __name__ == "__main__":
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main()
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