CRYPTOGRAPHY
The Art of Writting or Solving Codes.
Cryptography is method of storing and transmitting data in
a particular form so that only those for whom it is intended
can read and process it.
1 Kryptos - Hidden, secrat
2 Graphein - Writing
Two Main Goal:
1 Information Privacy
2 Authentication (Verify Identify)
PT: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
CT: R S T U V W X Y Z A B C D E F G I J K L M N O P Q R
Secrat Key - 17 (if know anbody He/She Decrypt the text)
Cryptograpy VS Stengnography
Cryptography:
The encrypted letter could be seen by anyone but cryptograpju
make the message not understandable
Stenography:
Stenograpy is hiding the message in another median so that
nobady will notice the message
Cryptography:
The end result in cryptography is the cipher text
Stenography:
The end result of information hiding is the stego-media
Steganography Cryptograpu
1 Transforming information into Yes Yes
a form incomprehensible thid
parties
2 Hidding Information No Yes
3 Key usage Yes Yes
4 Hiding the fact of No Yes
Communication
5 Ensuring anonymity of
communicating parties No Yes
6 The Amount of information (Comparable to the (Much greater than the
Transmitted in the communication amount of encrypted amount of encrypted
Information) Information)
7 Additional Carrier Needed No Yes
Pratical view:
Sender clear text (Hello)
Hello
Encryption text (%fd$jh)
%fd$jh
Decryption Text (Hello)
Hello
Types of Encryption
Symmetric Keys:
Encryption and decryption use the Same Key
Skyview Partners---------Encrypt--------7I$wPo^8a'!yUdSL-----Decrypt------Skyview Partners
Asymmetric Key:
Encryption and decryption use different keys, a public key and a private key
Encrypt use Privet key And Decryption public keys
Cipher
Ciphertext is encrypted text. Plaintext is what you have before
encryption, and ciphertext is the encrypted result.
The term cipher is sometimes used as a synonym for ciphertext,
but it more properly means the method of encryption rather than
the result.
Cipher is nothing more then an algorithm used for both encryption as
well as decryption.
Cipher types
1 Modern---------Subsitution-----transposition
2 Classic--------Private---------Public-------Stream-------Block