This document provides an overview of steganography and its modules for a PowerPoint presentation. Steganography is the art of hiding communication by concealing messages within other information. It uses various techniques to hide information in digital images or audio files. The presentation covers the encryption and decryption modules used for steganography. Encryption hides data in a host file using an algorithm while decryption extracts the data using the reverse algorithm. The modules create an application for encrypting and decrypting data files within media files to perform steganography.

1. A
POWER POINT PRESENTATION
ON
PBL TOPIC
STEGANOGRAPHY
Submitted By - Chirag Gupta
Pavan Yadav
Ashish Agarwal

2. Abstract-
Steganography is the art of hiding the fact that communication is taking
place, by hiding information in other information. Many different carrier
file formats can be used, but digital images are the most popular because
of their frequency on the internet , there exists a large variety of
steganography techniques.Steganography become more important as
more people join the cyberspace revolution. Steganography is the art of
concealing information in ways that prevents the detection of hidden
messages. Stegranography include an array of secret communication
methods that hide the message from being seen or
discovered.Steganography hide the secrete message within the host
data set and presence imperceptible and is to be reliably communicated
to a receiver. The host data set is purposely corrupted, but in a covert
way, designed to be invisible to an information analysis. Information
hiding is an emerging research area, which encompasses applications
such as copyright protection for digital media, watermarking,
fingerprinting, and steganography.

3. INTRODUCTION
The word steganography if of Greek origin and means "covered, or hidden
writing". Steganography is the art and science of communicating in a way
which hides the existence of the communication.
By contrast, cryptography obscures the meaning of a message, but it does not
conceal the fact that there is a message.
Steganography and cryptography
Cryptography--- the science of writing in secret codes--addresses all of the
elements necessary for secure communication over an insecure channel,
namely privacy, confidentiality, key exchange, authentication, and non-
repudiation.But cryptography does not always provide safe communication.
Consider an environment where the very use of encrypted message cause
suspicion.
The advantage of steganography over cryptography alone in that message do
not attract attention to themselves, to messengers, or to recipients. Whereas the
goaln of cryptography is to make data unreadable by a third party, the goal of
steganography is to hide the data from a third party. Often , steganography and
cryptography are used together to ensure security of the covert message.

4.  Encryption algorithm: This is the main key to any
cryptographic system. This encryption algorithm
subjects the plain text to various substitutions and
transformations.
 Secret key: The secret key is given by the user which
will act as an input to the encryption algorithm. Based on
this key, various substitutions and transformations on
the plain text will differ.
 Cipher text: This is the output generated by the
encryption algorithm. The cipher text is the jumbled text.
The cipher text differs with each and every secret key
that has given to the encryption algorithm.
 Decryption algorithm: This is opposite to the “encryption
algorithm”. It will acquire cipher text and secret key as
an input and produce plain text as an output.

5. Start Application
Encyption Decryption
Image file
BMP Image file
Image Message
IMAGE
Message
file

7. Hiding
Media File
Data File
Encyption
Algorithm
Ecrypted
File
Extraction Data File
Decryption
Algorithm

8. ENCRYPTION

9. DECRYPTION

10. MODULES:-
 1.Encyption:
Hiding Data Into a Image or Audio file using
Encryption Algorithm.
 2.Decryption:
Extracting Data from Encrypted file using Decryption
Algorithm.
 3.Application Design:
Creating a Application which will cover all the
functions of Steganography like Encryption and
Decryption.

11. MODULE 2 - DECRYPTION
 Decryption - Decryption is the process of taking
encoded or encrypted text or other data and
converting it back into text that you or the computer
can read and understand. This term could be used
to describe a method of un-encrypting the data
manually or with un-encrypting the data using the
proper codes or keys..
 If the data needs to be viewable, it may require
decryption. If a decryption passcode or key is not
available, special software may be needed to
decrypt the data using algorithms to crack the
decryption and make the data readable

12. HOW DECRYPTION WORKS
 The most successful algorithms use a key. A key is simply a
parameter to the algorithm that allows the encryption and
decryption process to occur.
 There are many modern key-based cryptographic techniques .
These are divided into two classes: symmetric and
asymmetric (also called public/private) key cryptography. In
symmetric key cryptography, the same key is used for both
encryption and decryption..
 Symmetric-key ciphers use the same key, or secret, for
encrypting and decrypting a message or file. The most widely
used symmetric-key cipher is AES, which was created to
protect government classified information. Symmetric-key
encryption is much faster than asymmetric encryption, but the
sender must exchange the key used to encrypt the data with
the recipient before he or she can decrypt it. This requirement
to securely distribute and manage large numbers of keys
means most cryptographic processes use a symmetric
algorithm to efficiently encrypt data, but use an asymmetric
algorithm to exchange the secret key.

13. LSB(Least Significant bit) substitition is the process of adjusting the carrier
image into

15. Decryption Process

16. Benefits of the Private/Public encryption key
 It does not matter if the public encryption key has been copied by a third party
as it cannot decrypt (open the box) messages
 The receiving party knows that the sender's encrypted message has not been
decrypted and viewed by a third party as that requires the private key of which
the receiver has the only copy
 The sender's encrypted message has not been decrypted, tampered with and
re-encrypted by a third party as that would required both the private and public
keys
Digital Signatures
This is similar to encrypting messages in that there is a private key and a public
key. The sender using their private key to generate a block of characters. The
block of characters depends on the content of the message and the private key.
This means that some unique identification can be obtained from the digital
signature when it is decrypted using the public key. When the digital signature is
verified using the public key it also verifies that the message text was used to
generate the digital signature. This prevents a third party making changes to a
message

18. SUBMITED BY:- SUBMITED TO:-
ASHISH AGARWAL PROF.SHOLA USHARANI
16MCA1051
MODEL 2
Decryption