2. Overview
• Introduction
• History
• Basic model
• Techniques
• Physical techniques
• Digital techniques
• Steganography vs Cryptography
• Application
• Conclusion
3. Introduction
• Steganography from the Greek word steganos
meaning “covered” and the Greek word graphie
meaning “writing”.
• Steganography is the science of hiding information.
• This can be achieved by concealing the existence of
information within seemingly harmless carriers or
cover.
• Carrier: Text, Image, Audio, Video, etc.
4. Example
Since everyone can read, encoding text
in neutral sentences is doubtfully effective
Since Everyone Can Read, Encoding Text
In Neutral Sentences Is Doubtfully Effective
‘Secret inside’
5. History
• The first recorded uses of steganography can
be traced back to 440BC when Herodotus
mentions two examples in his Histories.
• Demaratus sent a warning about a
forthcoming attack to Greece.
• Herodotus, who shaved the head of his most
trusted slave and tattooed a message on it.
After his hair had grown the message was
hidden.
8. Physical techniques
• Hidden messages within wax tablet.
• Hidden messages on messenger's body.
• Hidden messages on paper written in secret
inks
• Messages written in Morse code on yarn and
then knitted into a piece of clothing worn by a
courier.
• Null ciphers.
9.
10. Example of null cipher
• PRESIDENT'S EMBARGO RULING SHOULD
HAVE IMMEDIATE NOTICE. GRAVE SITUATION
AFFECTING INTERNATIONAL LAW. STATEMENT
FORESHADOWS RUIN OF MANY NEUTRALS.
YELLOW JOURNALS UNIFYING NATIONAL
EXCITEMENT IMMENSELY.
• PERSHING SAILS FROM NY JUNE I
11. Digital Techniques
• Concealing messages within the lowest bits
of noisy images or sound files.
• Chaffing and winnowing.
• Pictures embedded in video material.
• Steganography for audio signals.
• Hidden text within Web pages.
14. Steganography V/s Cryptography
Steganography
• Unknown message passing
• Steganography prevents
discovery of the very
existence of communication
• Little known technology
• Steganography does not
alter the structure of the
secret message
Cryptography
• Known message passing
• Encryption prevents an
unauthorized party from
discovering the contents of
a communication
• Common technology
• Cryptography alter the
structure of the secret
message
15. Steganography Terms
• Carrier or Cover File - A Original message or a file in
which hidden information will be stored inside of it .
• Stego-Medium - The medium in which the information
is hidden.
• Embedded or Payload - The information which is to be
hidden or concealed.
• Steganalysis - The process of detecting hidden
information inside a file.
16. Application
• Confidential communication and secret data
storing
• Protection of data alteration
• Usage in modern printers
• Alleged use by terrorists
• Alleged use by intelligence services