Substitution and transposition ciphers are two categories of ciphers used in classical cryptography. Substitution and transposition differ in how chunks of the message are handled by the encryption process. Substitution ciphers encrypt plaintext by changing the plaintext one piece at a time. Transposition ciphers encrypt plaintext by moving small pieces of the message around. A transposition cipher doesn't change the characters in the plaintext when it generates the cipher text, it just re-arranges them. It applies some kind of permutation function to the text to produce a re-arrangement, which can be reversed by knowing the secret to the permutation. In this report, I have chosen columnar transposition cipher. In a columnar transposition cipher, the message is written out row by row into the matrix. The matrix is based on the length of the keyword. If there is any blank space in the matrix, replace it with nulls. This method is for a regular columnar transposition cipher. For an irregular columnar transposition cipher, the spaces are left blank. Then read out the message column by column, and the columns are chosen in some scrambled order based on the keyword. For example, the word CODEC is of length 5, so the rows are of length 5, and the permutation is defined by the alphabetical order of the letters in the keyword. In this case, the order would be "1 5 3 4 2". In the case of repeated alphabet, numbering is based on left to right. In the case of CODEC, the first C is considered as 1 and the second C as 2.

...Mehran Sahami CS 106A
Handout #26 October 22, 2007
Strings and Ciphers
Based on a handout by Eric Roberts.
Cryptography, derived from the Greek word κρυπτοσ meaning hidden, is the science of creating and decoding secret messages whose meaning cannot be understood by others who might intercept the message. In the language of cryptography, the message you are trying to send is called the plaintext; the message that you actually send is called the ciphertext. Unless your...

...Security / e-Business Security
CAESER CIPHER – THE SHIFT CIPHER
1. Introduction
2. History & Development
3. How It Works
4. C++ Source Code [Encryption]
5. C++ Source Code [Decryption]
6. Step By Step Explanation [Decryption]
7. Step By Step Explanation [Decryption]
8. Pros & Cons
9. Conclusion
10. Reference
INTRODUCTION
In cryptography, a Caesar cipher, also known as Caesar's...

...ColumnarTransposition
Introduction
The ColumnarTranspositioncipher is very simple and easy to implement cipher. It is a transpositioncipher that follows a simple rule for mixing up the characters in the plaintext to form the cipher text.
How it works
In a columnartransposition, the message is written out in rows of a fixed length,...

...HILL CIPHER
TERM-PAPER
3/31/2013
LPU
vidit
Name: Vidit kumar Singh.
Reg no: 11009010
Roll no: B38.
Cap : 323.
Sub : Information Security and privacy.
INDEX
Introduction
Workings
Decryption
Matrix Inverse
Hill ciphers that encipher larger blocks
Ciphertext Attack
Known plaintext attack
Security
Key size
Diffusion and Confusion
Conclusion
References
Hill Cipher
Introduction...

...Brittany Lewis Cryptology and Cipher Codes Math Fair Report
In a world where identity theft is on the rise, hackers are hard at work trying to get people’s credit card numbers, and where companies are getting your information to sell you unwanted things, tight security has become a large factor of keeping the personal and confidential information of our society safe. Cryptology and Cipher codes are commonly used ways to keep...

...straightforward use of cryptography. Two people may communicate securely by encrypting the messages sent between them. The paper presents modifications of the Hill cipher generating dynamic encryption key matrix
Index Terms—Hill cipher, Matrix encryption, Permutation matrix
NOMENCLATURE :
Introduction:
INTRODUCTION
The Hill cipher (HC) algorithm [1] is one of the famous and known symmetric algorithms in the field of cryptography. HC is...

...
Q-How you accept project? Medium?
-online picking
-customer directly contact you?
Ans- Client sends the Request to the Head Office, according to the requirenment of Client project manager is assigned and respective team is located whether in any city. Clients contact to all of his resources. No Client physically visit to the Software house.
Q- Do you offer friendly working environment to stress out the workers?
Ans- yes, They provide indoor games and parties and provide time...

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