Steganography, Cryptography, and
There are two major branches of information hiding, Steganography and
– Communication in watermarking is the host signal, with the embedded data
providing copyright protection.
– The existence of a watermark is often declared openly.
– Any attempt to remove or invalidate the embedded content renders the host
Doesn’t conceal the communication.
Scrambles the data to prevent eavesdroppers understanding the content.
Cryptography involves various methods and implementations.
May be considered complementary and orthogonal (unrelated).
Once the presence of hidden information is revealed or even suspected, the
purpose of steganography is defeated.
History of Steganography
440 B.C. (physical and wax based)
1st and 2nd world wars.(letters)
Demeratus sent a warning about a forthcoming attack to Greece by writing it on a
wooden panel and covering it in wax.
Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it.
After his hair had grown the message was hidden. The purpose was to instigate a revolt
against the Persians.
World War II
Null ciphers (unencrypted messages):
Apparently neutral's protest is thoroughly discounted and ignored.
Isman hard hit. Blockade issue affects pretext for embargo on by
products, ejecting suets and vegetable oils.
Sent by a German Spy in WWII, by taking the second letter in each word the following
Pershing sails from NY June 1.
Shrinking messages down to the size of a dot became a popular method. Since the
microdot could be placed at the end of a sentence or above a j or an i .
Art and science of writing hidden
A form of security through
No one apart from the sender and
intended recipients suspects the
existence of messages.
Basics of Modern Steganography
steganographic function "embedding"
steganographic function "extracting"
cover data in which emb will be hidden
message to be hidden
parameter of fE
cover data with the hidden message
Steps In SteganographySteganography
The message"Boss said that
we should blow
up the bridge at
Watermarking of audio signals is more challenging compared to the watermarking
of images or video sequences, due to wider dynamic range of the HAS in
comparison with human visual system (HVS). The sensitivity of the HAS to the
additive white Gaussian noise (AWGN) is high as well; this noise in a sound file can
be detected as low as 70 dB.
Some commonly used methods of audio steganography are discussed below-.
Least Significant Bit (LSB) Coding : One of the earliest techniques studied in the
information hiding of digital audio (as well as other media types) is LSB coding. In
this technique LSB of binary sequence of each sample of digitized audio file is
replaced with binary equivalent of secret message.
Parity Coding : Instead of breaking a signal down into individual samples, the parity
coding method breaks a signal down into separate regions of samples and encodes
each bit from the secret message in a sample region's parity bit. If the parity bit of a
selected region does not match the secret bit to be encoded, the process flips the
LSB of one of the samples in the region.
Advantage: The sender has more of a choice in encoding the secret bit, and the
signal can be changed in a more unobtrusive manner.
Disadvantage: This method like LSB coding is not robust in nature.
• Algorithm of hiding
in video files:
Users and Applications-:
in a haystack is
•So we hope in
gonna detect the
smallest and tiniest
of sentences in the
Huge text, audio
and video files