CSF_ACW_1/file_steg/file_steg.py

154 lines
5.1 KiB
Python
Executable File

import numpy as np
class file_steg:
def __init__(self, file: str = None, bit_positions: list[int] = None) -> None:
"""
Initialize the class
:param file: Path to the file to encode or decode
:type file: str
:param bit_positions: Bit to hide the data in (1 - LSB to 8 - MSB)
:type bit_positions: list[int]
"""
self.supported_extensions = [
"mp3",
"mp4",
"docx",
"xlsx",
"pptx"
]
if file is None:
raise ValueError(f"[-] Error: File path is required")
if file.split(".")[-1] not in self.supported_extensions:
raise ValueError(f"[-] Error: File extension {file.split('.')[-1]} is not supported")
self.file = file
self.bits_to_hide = [8 - bit_pos for bit_pos in bit_positions] if bit_positions else [1] # Default is LSB
self.delimiter = "LZu30,#" # Delimiter to indicate the end of the secret data
def encode(self, secret_data_str: str = "Hello World") -> bytes:
"""
Encode the secret data into the mp3 file
:param secret_data_str: String of data to hide
:return: Encoded mp3 file as bytes
:rtype: bytes
"""
with open(self.file, "rb") as f:
data = f.read()
# Max Bytes to encode
n_bytes = len(data) >> 3
if len(secret_data_str) > n_bytes:
raise ValueError(
f"[-] Error: Binary Secret data length {len(secret_data_str)} is greater than data length {n_bytes}")
# Convert secret data to binary
binary_secret_data = self.to_bin(secret_data_str)
# Add delimiter
binary_secret_data += self.to_bin(self.delimiter)
data_index = 0
encoded_data = bytearray()
print(f"[+] Starting encoding...")
for byte in data:
if data_index >= len(binary_secret_data):
encoded_data.append(byte)
else:
for bit_pos in self.bits_to_hide:
if data_index < len(binary_secret_data):
byte = list(format(byte, "08b"))
byte = list(byte)
byte[bit_pos] = binary_secret_data[data_index]
data_index += 1
# Convert byte back to int
byte = int("".join(byte), 2)
encoded_data.append(byte)
print(f"[+] Encoding completed successfully.")
return bytes(encoded_data)
def decode(self) -> str:
"""
Decode the secret data from the mp3 file
:return: Decoded secret data
:rtype: str
"""
with open(self.file, "rb") as f:
data = f.read()
binary_data = ""
print(f"[+] Starting decoding...")
for byte in data:
# Add byte to binary data
# Convert byte from int to binary string
byte = format(byte, "08b")
# Pad byte with 0's to make sure it has 8 bits
byte = "0" * (8 - len(byte)) + byte
for bit_pos in self.bits_to_hide:
binary_data += byte[bit_pos]
all_bytes = [binary_data[i: i + 8] for i in range(0, len(binary_data), 8)]
decoded_data = ""
for byte in all_bytes:
decoded_data += chr(int(byte, 2))
if decoded_data[-len(self.delimiter):] == self.delimiter:
break
print(f"[+] Decoding completed successfully.")
# Return the decoded data
return decoded_data[:-len(self.delimiter)]
def to_bin(self, data: str) -> str | list[str]:
"""
Convert text file data to binary format as string
:param data: String
:type data: str
:return: Binary Data: String | List[String]
"""
if isinstance(data, str):
return ''.join([format(ord(i), "08b") for i in data])
elif isinstance(data, bytes) or isinstance(data, np.ndarray):
return [format(i, "08b") for i in data]
elif isinstance(data, int) or isinstance(data, np.unit8):
return format(data, "08b")
else:
raise TypeError("Type not supported")
if __name__ == "__main__":
with open("../Txt_Steg/secret_data.txt", "r") as f:
secret_data = f.read()
bits_to_hide = np.random.choice(range(1, 9), np.random.randint(1, 9), replace=False)
bits_to_hide = list(bits_to_hide)
bits_to_hide.sort()
print(f"Bits to hide: {bits_to_hide}")
mp3_file = "audio.mp3"
mp4_file = "video.mp4"
docx_file = "test.docx"
output_file_mp3 = "encoded_audio.mp3"
output_file_mp4 = "encoded_video.mp4"
output_docx_file = "encoded_test.docx"
# Encode data, get as bytes
encoded_data = file_steg(file=mp3_file, bit_positions=bits_to_hide).encode(secret_data_str=secret_data)
# Write encoded data to file
with open(output_file_mp3, "wb") as f:
f.write(encoded_data)
# Decode data from mp3 file
decoded_data = file_steg(file=output_file_mp3, bit_positions=bits_to_hide).decode()
# Print the decoded data
print("[+] Decoded data:", decoded_data)