Authors :
P. Arunkumar; S. Divya; E. Baskar; R. Brindha Devi
Volume/Issue :
Volume 9 - 2024, Issue 3 - March
Google Scholar :
https://tinyurl.com/2hh5t34u
Scribd :
https://tinyurl.com/42c2m4n5
DOI :
https://doi.org/10.38124/ijisrt/IJISRT24MAR1334
Abstract :
Cryptography and Steganography are two
major forms of enforcing data privacy, with the former
being prevalent. For small payloads, Steganography is
preferred, as the data remains concealed and abstracted.
The process involves embedding bits onto a carrier image.
However, the disadvantage of steganography is that the
carrier image gets distorted, which is a major concern when
it comes to pixel sensitive images, such as forensic and
medical images that aremission critical. Furthermore, due
to modifications in the pixel values, the images get distorted,
which can be irrecoverable. Hence, the technique of
Reversible Data Hiding(RDH) can be used as a solution.
Usually two methods are used under RDH, namely
Histogram Shifting (HS) and Difference Expansion (DE).
Histogram Shifting method shifts all pixel values
between pairs of peak and zero points, which allows data to
be embedded in the intermediate points. However, this
method also depends on frequencies of pixel values on the
image, andthe embedding capacity varies greatly on the
image. In Difference Expansion Method, the difference
between a pixel and its adjacent pixels is considered to
embed a single bit intoone of the pixels. Here, a scheme to
embed multiple bits in a pixel is proposed, which greatly
enhances the embedding capacity. Initially, three
horizontally adjacent pixels are takenand the difference
between the rightmost and leftmost pixel iscalculated.
This difference is used to classify the centre pixel as
embeddable or non-embeddable. If the pixel is embeddable,
anew pixel value is calculated, which comprises of the secret
bits, offset bits and flag bits, without the use of any
difference expansion or histogram shifting process. The
secret bits and the original pixel value can be easily
recovered from the modified value using the offset and flag
bits. This scheme has higher embedding capacity, and lower
complexity in terms of computations, when comparedwith
other RDH schemes.
Keywords :
Information Security, Steganography, Reversible Data Hiding, HistogramShifting, Difference Expansion,Carrier Image.
Cryptography and Steganography are two
major forms of enforcing data privacy, with the former
being prevalent. For small payloads, Steganography is
preferred, as the data remains concealed and abstracted.
The process involves embedding bits onto a carrier image.
However, the disadvantage of steganography is that the
carrier image gets distorted, which is a major concern when
it comes to pixel sensitive images, such as forensic and
medical images that aremission critical. Furthermore, due
to modifications in the pixel values, the images get distorted,
which can be irrecoverable. Hence, the technique of
Reversible Data Hiding(RDH) can be used as a solution.
Usually two methods are used under RDH, namely
Histogram Shifting (HS) and Difference Expansion (DE).
Histogram Shifting method shifts all pixel values
between pairs of peak and zero points, which allows data to
be embedded in the intermediate points. However, this
method also depends on frequencies of pixel values on the
image, andthe embedding capacity varies greatly on the
image. In Difference Expansion Method, the difference
between a pixel and its adjacent pixels is considered to
embed a single bit intoone of the pixels. Here, a scheme to
embed multiple bits in a pixel is proposed, which greatly
enhances the embedding capacity. Initially, three
horizontally adjacent pixels are takenand the difference
between the rightmost and leftmost pixel iscalculated.
This difference is used to classify the centre pixel as
embeddable or non-embeddable. If the pixel is embeddable,
anew pixel value is calculated, which comprises of the secret
bits, offset bits and flag bits, without the use of any
difference expansion or histogram shifting process. The
secret bits and the original pixel value can be easily
recovered from the modified value using the offset and flag
bits. This scheme has higher embedding capacity, and lower
complexity in terms of computations, when comparedwith
other RDH schemes.
Keywords :
Information Security, Steganography, Reversible Data Hiding, HistogramShifting, Difference Expansion,Carrier Image.
