131 lines
4.2 KiB
Python
131 lines
4.2 KiB
Python
import numpy as np
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class file_steg:
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def __init__(self, file: str = None, bit_positions: list[int] = None) -> None:
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"""
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Initialize the class
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:param file: Path to the file to encode or decode
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:type file: str
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:param bit_positions: Bit to hide the data in (1 - LSB to 8 - MSB) Default is LSB (index = 7)
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:type bit_positions: list[int]
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"""
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self.supported_extensions = [
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"mp3",
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"mp4",
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"docx",
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"xlsx",
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"csv",
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"pptx",
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"pdf"
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]
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if file is None:
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raise ValueError(f"[-] Error: File path is required")
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if file.split(".")[-1] not in self.supported_extensions:
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raise ValueError(f"[-] Error: File extension {file.split('.')[-1]} is not supported")
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else:
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self.file = file
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self.bits_to_hide = [8 - bit_pos for bit_pos in bit_positions] if bit_positions else [7] # Default is LSB
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self.delimiter = "LZu30,#" # Delimiter to indicate the end of the secret data
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def encode(self, secret_data_str: str = "Hello World") -> bytes:
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"""
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Encode the secret data into the mp3 file
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:param secret_data_str: String of data to hide
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:return: Encoded mp3 file as bytes
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:rtype: bytes
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"""
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with open(self.file, "rb") as f:
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data = f.read()
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# Max Bytes to encode
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n_bytes = len(data) * 8 * len(self.bits_to_hide)
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if len(secret_data_str) * 8 > n_bytes:
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raise ValueError(
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f"[-] Error: Binary Secret data length {len(secret_data_str)} is greater than data length {n_bytes}")
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# Convert secret data to binary
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binary_secret_data = self.to_bin(secret_data_str)
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# Add delimiter
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binary_secret_data += self.to_bin(self.delimiter)
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data_index = 0
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encoded_data = bytearray()
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for byte in data:
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if data_index >= len(binary_secret_data):
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encoded_data.append(byte)
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else:
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for bit_pos in self.bits_to_hide:
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if data_index < len(binary_secret_data):
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byte = list(format(byte, "08b"))
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byte = list(byte)
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byte[bit_pos] = binary_secret_data[data_index]
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data_index += 1
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# Convert byte back to int
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byte = int("".join(byte), 2)
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encoded_data.append(byte)
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return bytes(encoded_data)
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def decode(self) -> str:
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"""
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Decode the secret data from the mp3 file
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:return: Decoded secret data
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:rtype: str
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"""
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with open(self.file, "rb") as f:
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data = f.read()
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binary_data = ""
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decoded_data = ""
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for byte in data:
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# Add byte to binary data
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# Convert byte from int to binary string
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byte = format(byte, "08b")
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# Pad byte with 0's to make sure it has 8 bits
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byte = "0" * (8 - len(byte)) + byte
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for bit_pos in self.bits_to_hide:
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binary_data += byte[bit_pos]
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all_bytes = [binary_data[i: i + 8] for i in range(0, len(binary_data), 8)]
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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 the decoded data
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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 text file data to binary format as string
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:param data: String
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:type data: str
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:return: Binary Data: String | List[String]
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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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