EchoHiding

stegobox.codec.EchoHiding

Bases: BaseCodec

Echo Data Hiding places embedded text in the cover audio by introducing an "echo". Digital tags are defined using four major parameters of the echo: initial amplitude, decay rate, "zero" offset, and "one" offset (offset + delta). As the offset (delay) between the original and the echo decreases, the two signals blend. At a certain point the truman ear hears not an original signal and an echo, but rather a single distorted signal.

Originally implemented in evrrn/bachelors_thesis_steganography

Source code in stegobox/codec/echo_hiding/echo_hiding.py

class EchoHiding(BaseCodec):
    """Echo Data Hiding places embedded text in the cover audio by introducing an
    "echo". Digital tags are defined using four major parameters of the echo: initial
    amplitude, decay rate, "zero" offset, and "one" offset (offset + delta). As the
    offset (delay) between the original and the echo decreases, the two signals blend.
    At a certain point the truman ear hears not an original signal and an echo, but
    rather a single distorted signal.


    Originally implemented in
    [evrrn/bachelors_thesis_steganography](https://github.com/evrrn/bachelors_thesis_steganography)
    """

    def __init__(self) -> None:
        super().__init__()

    def encode(self, carrier, payload):
        """Encoder requires carrier audio to be WAV and payload to be a txt file.

        Args:
            carrier: Carrier audio in format WAV. Read with
                'stegobox.io.audio.read_r()'.
            payload: Secret message to be encoded. Payload in format txt. Read with
                `stegobox.io.txt.read()`.

        Returns:
            encoded_key: Information of the echo.
            encoded_audio: Encoded audio in format wav with the payload embeded.
            params: Audio information.
        """
        signal = Wave(carrier)
        message = CoderBinaryMessage(payload)
        key = CoderKey()

        stegosystem = CoderSystem(signal, message, key)
        encoded_key = stegosystem.create_stego()
        encoded_audio, params = stegosystem.signal.create_stegoaudio(stegosystem.key)
        return encoded_key, encoded_audio, params

    def decode(self, _):
        raise NotImplementedError("This codec does not support decoding without key")

    def decode_with_key(self, carrier, key):
        """Decode the secret payload from the carrier audio.

        Args:
            carrier: Encoded carrier audio.
            key: Information of the echo provided by the sender.

        Returns:
            The revealed payload (secret message).
        """
        encoded_signal = Wave(carrier)
        decode_message = DecoderBinaryMessage()
        decode_key = DecoderKey(key)

        stegosystem = DecoderSystem(encoded_signal, decode_message, decode_key)
        return stegosystem.extract_stegomessage()

encode(carrier, payload)

Encoder requires carrier audio to be WAV and payload to be a txt file.

Parameters:

Name	Type	Description	Default
carrier		Carrier audio in format WAV. Read with 'stegobox.io.audio.read_r()'.	required
payload		Secret message to be encoded. Payload in format txt. Read with stegobox.io.txt.read().	required

Returns:

Name	Type	Description
encoded_key		Information of the echo.
encoded_audio		Encoded audio in format wav with the payload embeded.
params		Audio information.

Source code in stegobox/codec/echo_hiding/echo_hiding.py

def encode(self, carrier, payload):
    """Encoder requires carrier audio to be WAV and payload to be a txt file.

    Args:
        carrier: Carrier audio in format WAV. Read with
            'stegobox.io.audio.read_r()'.
        payload: Secret message to be encoded. Payload in format txt. Read with
            `stegobox.io.txt.read()`.

    Returns:
        encoded_key: Information of the echo.
        encoded_audio: Encoded audio in format wav with the payload embeded.
        params: Audio information.
    """
    signal = Wave(carrier)
    message = CoderBinaryMessage(payload)
    key = CoderKey()

    stegosystem = CoderSystem(signal, message, key)
    encoded_key = stegosystem.create_stego()
    encoded_audio, params = stegosystem.signal.create_stegoaudio(stegosystem.key)
    return encoded_key, encoded_audio, params

decode_with_key(carrier, key)

Decode the secret payload from the carrier audio.

Parameters:

Name	Type	Description	Default
carrier		Encoded carrier audio.	required
key		Information of the echo provided by the sender.	required

Returns:

Type	Description
	The revealed payload (secret message).

Source code in stegobox/codec/echo_hiding/echo_hiding.py

def decode_with_key(self, carrier, key):
    """Decode the secret payload from the carrier audio.

    Args:
        carrier: Encoded carrier audio.
        key: Information of the echo provided by the sender.

    Returns:
        The revealed payload (secret message).
    """
    encoded_signal = Wave(carrier)
    decode_message = DecoderBinaryMessage()
    decode_key = DecoderKey(key)

    stegosystem = DecoderSystem(encoded_signal, decode_message, decode_key)
    return stegosystem.extract_stegomessage()