1. Prof. Neeraj Bhargava
Mrs. Shubha Chaturvedi
Department of Computer Science, School of Engineering & System Sciences
MDS University Ajmer, Rajasthan
2. There are two basic building blocks of all
Encryption Techniques:
1. SUBSTITUTION
2. TRANSPOSITION.
4. A Substitution Technique is one in
which the letters of plaintext are
replaced by other letters or by
numbers or symbols. If the plaintext is
viewed as a sequence of bits, then
substitution involves replacing
plaintext bit patterns with cipher text
bit patterns.
5. The substitution cipher always replaces a plain text
symbol to obtain a cipher text symbol whereas
transposition cipher does not change the character
in the plain text when it generates the cipher text it
just rearrange them like anagram
It hides the message by rearranging the letter order
without altering the actual letter used .
It applies some kind of permutation function to the
text to produce rearrangement , which can be
reversed if you know the secret to permutation .
6. It is Product Cipher is a combination of
substitution and Transposition cipher.
Product cipher, data encryption scheme in
which the cipher text produced by
encrypting a plaintext document is
subjected to further encryption. By
combining two or more simple transposition
ciphers or substitution ciphers , a more
secure encryption may result.
