چکیده (انگلیسی):

Data protection from malicious attacks and misuse has become a
crucial issue. Various types of data, including images, videos, audio and
text documents, have given cause for the development of different methods
for their protection. Cryptography, digital signatures and steganography are
the most well known technologies used to protect data. During the last
decade, digital watermarking technology has also been utilized as an
alternative to prevent media forgery and tampering or falsification to ensure
both copyright and authentication. Much work has been done to protect
images, videos and audio but only a few algorithms have been considered
for text document protection with digital watermarking. However, our
survey observed that available text watermarking algorithms are neither
robust nor imperceptible and as such remain unsecured methods of
protection. Hence, research to improve the performance of text watermarking
algorithms is required. This paper reviews current watermarking algorithms
for text documents and categorizes text watermarking methods based on the
way the text was treated during the watermarking process. It also discusses
merits and demerits of available methods as well as recent proposed
methods for evaluating text watermarking systems and the need for further
research on digital text watermarking.