28-08-2013, 04:43 PM
SECRET COMMUNICATION THROUGH AUDIO FOR DEFENSE APPLICATION
[attachment=57554]
Abstract
A steganographic method of embedding textual information in an audio file is presented in this paper. In the
proposed technique, first the audio file is sampled and then an appropriate bit of each alternate sample is altered to embed the
textual information. As a steganographic approach the perceptual quality of the host audio signal was not to be degraded. In
this paper we propose Secret communication through Audio with Textual Information using Steganography method.
Steganography is an art of sending hidden data or secret messages over a public channel so that a third party cannot detect
the presence of the secret messages. The goal of steganography is different from classical encryption, which seeks to conceal
the content of secret messages; steganography is about hiding the very existence of the secret messages. Modern
steganography is generally understood to deal with electronic media rather than physical objects. There have been numerous
proposals for protocols to hide data in channels containing pictures, video, audio and even typeset text. This makes sense for
a number of reasons. First of all, because the size of the information is generally quite small compared to the size of the data
in which it must be hidden (the cover text), electronic media is much easier to manipulate in order to hide data and extract
messages. Secondly, extraction itself can be automated when the data is electronic, since computers can efficiently
manipulate the data and execute the algorithms necessary to retrieve the messages. Electronic data also often includes
redundant, unnecessary and unnoticed data spaces which can be manipulated in order to hide messages.
INTRODUCTION
Steganography is an art of sending hidden data or
secret messages over a public channel so that a third
party cannot detect the presence of the secret
messages. The goal of steganography is different
from classical encryption, which seeks to conceal the
content of secret messages; steganography is about
hiding the very existence of the secret messages.
Modern steganography is generally understood to
deal with electronic media rather than physical
objects. There have been numerous proposals for
protocols to hide data in channels containing pictures
[1, 2, 3], video [3, 4], audio [1, 3] and even typeset
text [1, 3]. This makes sense for a number of reasons.
First of all, because the size of the information is
generally quite small compared to the size of the data
in which it must be hidden (the cover text),
electronic media is much easier to manipulate in
order to hide data and extract messages. Secondly,
extraction itself can be automated when the data is
electronic, since computers can efficiently manipulate
the data and execute the algorithms necessary to
retrieve the messages. Electronic data also often
includes redundant, unnecessary and unnoticed data
spaces which can be manipulated in order to hide
messages.
ASSUMPTION AND SCOPE
Modern steganography based on embedding of
secret data into electronic media like image [1, 2, 3],
audio [1, 3], video [3, 4] and text [1, 3]. For example,
to a computer, an image is an array of numbers that
represent light intensities at various pixels. A
common image size is 640 × 480 pixels and 256
colors (or 8 bits per pixel). Such an image could
contain about 300 kilobits of data [5]. Digital images
are typically stored in either 24 bit or 8 bit files. A 24
bit image provides the most space for hiding
information. A data – embedding technique into an
audio file can be based on frequency masking [6],
temporal masking [7], bit modification [8], LSB
based method based on lifting wavelet transform [9]
etc.
RELATED WORKS
A survey of steganographic techniques [15]
reveals that there have been several techniques for
hiding information or messages in host messages in
such a manner that the embedded data should be
imperceptible.
Substitution system [15] substitutes redundant
parts of a cover with a secret message. Spread
spectrum techniques adopt ideas from spread
spectrum communication [3]. The statistical method
encodes information by changing several statistical
properties of a cover and use hypothesis testing in the
extraction process [3]. Distortion process stores
information by signal distortion and measure the
deviation from the original cover in the decoding step
[15]. The cover generation method encodes
information in the way a cover for secret
communication is created [3]. In case of hiding
information in digital sound, phase Coding [16]
embeds data by altering the phase in a predefined
manner. To a certain extent, modifications of the
phase of a signal cannot be perceived by the human
auditory system (HAS) [6].
ALGORITHM
To develop this algorithm multiple bits of each
sample of the file have been changed or modified to
insert text data in it. It has also been observed the
degradation of the host audio file after modification
of the bits. The bit modification was done by various
ways, like 1, 2, 3, 4 bits were changed in turn. But
after going through all the modification it has been
observed that 1 bit change in LSB gave the best
result. Thus, data can be embedded according to the
following algorithm
CONCLUSION
A method of embedding text-based data into a host
audio file using the method of bit modification has
been presented in this paper. A procedure has been
developed in which the data field is edited to embed
intended data into the audio file. To proceed with
this, the header section of the audio has been checked
perfectly because a minimal change in the header
section may leads to a corruption of whole audio file.
In this algorithm, as an experiment first 50 bytes
have been left untouched and starting from the 51st
bytes every alternate sample has been modified to
embed textual information. How the performance is
affected by changing different bit fields has not been
reported in this work.
[attachment=57554]
Abstract
A steganographic method of embedding textual information in an audio file is presented in this paper. In the
proposed technique, first the audio file is sampled and then an appropriate bit of each alternate sample is altered to embed the
textual information. As a steganographic approach the perceptual quality of the host audio signal was not to be degraded. In
this paper we propose Secret communication through Audio with Textual Information using Steganography method.
Steganography is an art of sending hidden data or secret messages over a public channel so that a third party cannot detect
the presence of the secret messages. The goal of steganography is different from classical encryption, which seeks to conceal
the content of secret messages; steganography is about hiding the very existence of the secret messages. Modern
steganography is generally understood to deal with electronic media rather than physical objects. There have been numerous
proposals for protocols to hide data in channels containing pictures, video, audio and even typeset text. This makes sense for
a number of reasons. First of all, because the size of the information is generally quite small compared to the size of the data
in which it must be hidden (the cover text), electronic media is much easier to manipulate in order to hide data and extract
messages. Secondly, extraction itself can be automated when the data is electronic, since computers can efficiently
manipulate the data and execute the algorithms necessary to retrieve the messages. Electronic data also often includes
redundant, unnecessary and unnoticed data spaces which can be manipulated in order to hide messages.
INTRODUCTION
Steganography is an art of sending hidden data or
secret messages over a public channel so that a third
party cannot detect the presence of the secret
messages. The goal of steganography is different
from classical encryption, which seeks to conceal the
content of secret messages; steganography is about
hiding the very existence of the secret messages.
Modern steganography is generally understood to
deal with electronic media rather than physical
objects. There have been numerous proposals for
protocols to hide data in channels containing pictures
[1, 2, 3], video [3, 4], audio [1, 3] and even typeset
text [1, 3]. This makes sense for a number of reasons.
First of all, because the size of the information is
generally quite small compared to the size of the data
in which it must be hidden (the cover text),
electronic media is much easier to manipulate in
order to hide data and extract messages. Secondly,
extraction itself can be automated when the data is
electronic, since computers can efficiently manipulate
the data and execute the algorithms necessary to
retrieve the messages. Electronic data also often
includes redundant, unnecessary and unnoticed data
spaces which can be manipulated in order to hide
messages.
ASSUMPTION AND SCOPE
Modern steganography based on embedding of
secret data into electronic media like image [1, 2, 3],
audio [1, 3], video [3, 4] and text [1, 3]. For example,
to a computer, an image is an array of numbers that
represent light intensities at various pixels. A
common image size is 640 × 480 pixels and 256
colors (or 8 bits per pixel). Such an image could
contain about 300 kilobits of data [5]. Digital images
are typically stored in either 24 bit or 8 bit files. A 24
bit image provides the most space for hiding
information. A data – embedding technique into an
audio file can be based on frequency masking [6],
temporal masking [7], bit modification [8], LSB
based method based on lifting wavelet transform [9]
etc.
RELATED WORKS
A survey of steganographic techniques [15]
reveals that there have been several techniques for
hiding information or messages in host messages in
such a manner that the embedded data should be
imperceptible.
Substitution system [15] substitutes redundant
parts of a cover with a secret message. Spread
spectrum techniques adopt ideas from spread
spectrum communication [3]. The statistical method
encodes information by changing several statistical
properties of a cover and use hypothesis testing in the
extraction process [3]. Distortion process stores
information by signal distortion and measure the
deviation from the original cover in the decoding step
[15]. The cover generation method encodes
information in the way a cover for secret
communication is created [3]. In case of hiding
information in digital sound, phase Coding [16]
embeds data by altering the phase in a predefined
manner. To a certain extent, modifications of the
phase of a signal cannot be perceived by the human
auditory system (HAS) [6].
ALGORITHM
To develop this algorithm multiple bits of each
sample of the file have been changed or modified to
insert text data in it. It has also been observed the
degradation of the host audio file after modification
of the bits. The bit modification was done by various
ways, like 1, 2, 3, 4 bits were changed in turn. But
after going through all the modification it has been
observed that 1 bit change in LSB gave the best
result. Thus, data can be embedded according to the
following algorithm
CONCLUSION
A method of embedding text-based data into a host
audio file using the method of bit modification has
been presented in this paper. A procedure has been
developed in which the data field is edited to embed
intended data into the audio file. To proceed with
this, the header section of the audio has been checked
perfectly because a minimal change in the header
section may leads to a corruption of whole audio file.
In this algorithm, as an experiment first 50 bytes
have been left untouched and starting from the 51st
bytes every alternate sample has been modified to
embed textual information. How the performance is
affected by changing different bit fields has not been
reported in this work.