28-01-2013, 03:56 PM
Digital Steganography for Information Security
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ABSTRACT
The phenomenal growth in e-commerce applications through the Internet in the past
few years has led to a genuine need, as well as a sense of urgency, for both small
office and home office (SOHO) and corporate users to protect their data transactions
through the Internet. These data transactions may include sensitive document
transfer, digital signature authentication, digital watermarking for copyright
protection, and digital data storage and linkage.
In this paper, the use of digital steganography for information security in various ecommerce
applications through the Internet will be discussed in detail. These
applications include digital watermarking for copyright protection of multimedia
data, digital signature authentication and validation of electronic documents, digital
data storage and linkage for binding digitized photographs with personal attribute
information, as well as secure communication of multimedia data through the open
channels. Enhanced information security will lead to wider e-commerce applications
that involve e-communication, e-transactions, e-filing, and e-publications.
INTRODUCTION
The conventional way of securing data transactions is through the use of standard encryption key
techniques such as RSA, DES, and 3DES. In the past three years, however; a new branch of data security
techniques known as digital steganography has evolved and is continuing to receive a great deal of
attention from both the academic and industrial communities [1,2]. Since then, a number of companies
have established in the US and Europe to commercialize and market steganography products. Many of
these steganography products were developed as plug-ins and OEM applications.
Instead of scrambling the data using either a standard symmetric or asymmetric key system as in the case of
encryption, digital steganography exploits the use of a host data or message (also known as a container) to
hide or embed another data or message into it. Unlike encryption, the host data or container used in
steganography is not scrambled or hidden during the communication process. Only a hashed form of the
hidden data derived from a mathematical combination of the host and hidden data is transmitted for
decoding.
DIGITAL STEGANOGRAPHY
The applications of digital steganography in various e-commerce applications through the Internet will be
discussed in detail. These applications include digital watermarking for copyright protection of multimedia
data, digital signature authentication and validation of electronic documents, digital data storage and
linkage for binding digitized photographs with personal attribute information, as well as secure
communication of multimedia data. Targeting these applications, DataMark Technologies (DMT) have
developed four digital steganography products based on their patent-pending algorithms [3,4,5], as follows:
1. Secure Communication (StegCommTM)
2. Digital Signature Authentication (StegSignTM)
3. Digital Watermarking (StegMarkTM)
4. Digital Storage and Linkage (StegSafeTM)
SECURE COMMUNICATION
StegCommTM is a state-of-the-art digital steganography software package developed by DMT for
confidential multimedia communication. The software allows the user to select a multimedia data file or
"container" for embedding hidden text, audio sequence, video clip, or any form of data file. Figure 1
illustrates the basic concept of digital steganography when applied to text encoding. The contents of the
text message are hashed with those of the container file to produce a key file. The key file is also known as
a “Stegfile”.
Many conventional steganography techniques simply incorporate a combination of cryptography and
steganography. The cryptography operation is used first to scramble the hidden text. For steganography
operation, the scrambled data is then inserted or "hidden" into the least significant bits (LSB) of the
container data. One of the common drawbacks of these techniques is that the container file has to be of
certain size greater than the hidden file. Other limitations include the knowledge required on the exact
location of the hidden text, the limited container data formats, and the export restriction of using encryption
algorithms to certain countries. These difficulties are circumvented by the use of StegComm™. First,
StegCommTM utilises a patent-pending lossless algorithm (the HTTY algorithm) that does not affect the
data integrity of the container file. Second, the program is completely independent of the size of the
container file relative to that of the hidden file. Third, as steganography is a relatively new field, there are
currently no export restrictions on products that incorporate this technology.
DIGITAL SIGNATURE AUTHENTICATION
StegSignTM is a software product specifically developed by DMT to prevent malicious tampering of private
and confidential documents. These documents include company memos, Emails and letters. StegSignTM can
provide a wide spectrum of applications in the e-commerce sector. Such e-commerce applications include
business transactions between banks and customers, legal document exchanges between lawyers and
clients, and scenarios involving non-repudiation issues. This product will detect any unwarranted tampering
and alert the receiver side immediately.
StegSignTM incorporates patent-pending algorithms filed by DMT. A digital signature and a multimedia
container password are embedded into the confidential document. The basic operation of StegSignTM is
illustrated through a data flow diagram as shown in figure 4. The digital signature can be inputted as a
handwritten signature or as a personal seal. The container password can either be a normal text string, an
image, or a binary file. For the Professional version, encryption is available to provide another added layer
of security for the "signed" document. More mathematical random lock combinations for data embedding
are also included in the Professional version. Figure 5 illustrates a typical GUI sample from StegSignTM.
DIGITAL WATERMARKING
StegMarkTM is a digital watermarking software for copyright protection of digital images, music CDs,
DVDs, and other forms of multimedia data. In the case of digital images, the files can come from a variety
of sources, such as the Internet, digital still cameras, and video cameras. Many digital watermarking
techniques in the market embed only a certain number of bits or characters into the image. However,
StegMarkTM can embed either a text or image watermark invisibly into an "unlabelled" image. The text
watermark can be of many characters, for example, for a colour image of size 512 x 512, more than a few
thousand characters may be embedded.
The image watermark technique of StegMarkTM is currently the only digital watermarking product
available in the market that offers the embedding of a company's logo/trademark into an image. For a 512 x
512 image, an image watermark of size up to 128 x 128 can be embedded entirely into the image, without
the loss of image integrity. This unique "image-in-image" watermarking technique has already been filed
for an international patent and is currently under pending status.
LINKAGE AND STORAGE
StegSafeTM is the latest of DMT steganography products that provides a secure data linkage between a
digital image and attribute text information. The attribute information can be any personal records such as
employee details, hospital patient medical records, or law enforcement records. Currently, many personal
records with ID photographs are manually or electronically filed. Tampering to these records, such as
changing the name, photograph, or medical conditions, can be performed if the hacker is able to gain
security access to the database.
The main function of StegSafeTM is to securely link the personal record and digital photograph together and
then create a hash file that can be safely stored in a database. This hash file is unique to and can only be
decoded with the original photograph and associated personal record. Tampering with any one of these files
will render the decoding process ineffective. The database administrator will be able to determine whether
these files have been modified, by checking the original hash file with the digitized photograph. An
optional password is also available to protect the hash file prior to data storage. The basic operation of
StegSafeTM is illustrated in figure 8 and a GUI sample of this product is shown in figure 9.
CONCLUSIONS
The use of digital steganography for Infosecurity in various e-commerce applications through the Internet
has been discussed in detail in this paper. These applications include digital watermarking for copyright
protection of multimedia data, digital signature authentication and validation of electronic documents,
digital data storage and linkage for binding digitized photographs with personal attribute information, as
well as secure communication of multimedia data through open channels. Digital steganography can
provide one of the safest and unrestricted information security tools in the market, and is poised to advance
the pace of growth of e-commerce applications in Singapore and beyond.