Hill Cipher Program Source Code
Hill Cipher Program Source Codes
Hill Cipher Program Source Code Download
Hill Cipher Program Source Code Free
Hill Cipher Program Source Code Example

In classical cryptography. Here is the source code of the Java Program to Implement the Hill Cypher. Hi.i need a code to encrypt an image using Hill Cipher on java program.plz help me. I cant find the java source code for this subject. In 1929 by Lester S. Hill Ask a new question Source code dCode retains ownership of the source.
The program should handle keys and text of unequal length, and should capitalize everything and discard non-alphabetic characters. (If your program handles non-alphabetic characters in another way, make a note of it.) Related tasks Caesar cipher Rot-13 Substitution Cipher.

In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. To encipher or encode is to convert information into cipher or code. In common parlance, “cipher” is synonymous with “code“, as they are both a set of steps that encrypt a message; however, the concepts are distinct in cryptography, especially classical cryptography.

Codes generally substitute different length strings of character in the output, while ciphers generally substitute the same number of characters as are input. There are exceptions and some cipher systems may use slightly more, or fewer, characters when output versus the number that was input.

In this post, we will discuss the Playfair Cipher. The Playfair cipher is a cryptographic technique that is used to encrypt/decrypt a message. The technique encrypts pairs of letters (bigrams or digrams), instead of single letters as in the simple substitution cipher and rather more complex Vigenère cipher systems then in use.

This calculator uses Hill cipher to encrypt/decrypt a block of text. Personoutline Timur schedule 2014-02-26 09:51:42. According to the definition in wikipedia, in classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraphic.

Working

The Playfair cipher uses a 5 by 5 table of letters. To generate the key, we will first fill the table row-wise with the letters of the key. We omit the repeating letters. After this, we fill the table with the remaining letters. We usually omit the letter i or j so that the number of letters in the table is 25. After the table is generated, we divide the message into the pairs of 2. Then for each pair, we look up the position of the letters in the table. Suppose the pair is XY and X is at position (x1,y1) and Y is at position (x2,y2), we choose the letters which are at position (x2,y1) and (x1,y2). If the pairs are (x,y1) and (x,y2), then we choose the letters at (x,y1+1) and (x,y2+1).
If the pairs are (x1,y) and (x2,y), then we choose the letters at (x1+1,y) and (x2+1,y).

For example, if the message is “helloworld” and the key is “test”. We will generate the following table:

The original message and the encrypted message will be:

We will use C++ to write this algorithm due to the standard template library support. Hence, we will write the program of the Playfair Cipher algorithm in C++, although, it’s very similar to C.

Encryption

INPUT:
line 1: message
line 2: key

OUTPUT:
line 1: Encrypted message

The following is the Playfair Cipher encryption algorithm program in C++.

OUTPUT:

Decryption

INPUT:
line 1: message
line 2: key

OUTPUT:
line 1: decrypted message

The following is the Playfair Cipher decryption algorithm program in C++.

OUTPUT:

Other cryptography algorithms:

Let us know in the comments if you are having any questions regarding this cryptography cipher Algorithm.

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In this example, you will learn simpleC++ program to encrypt and decrypt the string using two different encryption algorithms i.e. Caesar Cypher and RSA.

Encryption/Decryption using Caesar Cypher Algorithm

Encryption/Decryption using RSA Algorithm

Encryption basically means encoding a particular message or information so that it can’t be read by other person and decryption is the process of decoding that message to make it readable.

Method 1: C++ program to encrypt and decrypt the string using Caesar Cypher Algorithm.

We have used a simple method of adding and subtracting a key value for encryption and decryption.

For encrypting a string, key-value ‘2’ is added to the ASCII value of the characters in the string.

Similarly, for decrypting a string, key-value ‘2’ is subtracted from the ASCII value of the characters.

Let’s take a deeper look at the source code:

Output

#Encrypting

#Decrypting

Explanation

In the above program, if you change the value of key then the encrypted value will be different.

If the user enters other value than 1 or 2 it will show Invalid Input.

Method 2: C++ program to encrypt and decrypt the string using RSA algorithm.

RSA algorithm is bit complex than Ceaser Cypher. It involves the use of public and private key, where the public key is known to all and used for encryption.

Hill Cipher Program Source Code

On the other hand, Private key is only used to decrypt the encrypted message.

Here is the deeper look at the steps of encryption algorithm:

1: Creating Keys

Select two large prime numbers x and y
Compute n = x * y
where n is the modulus of private and the public key
Calculate totient function, ø (n) = (x − 1)(y − 1)
Choose an integer e such that e is coprime to ø(n) and 1 < e < ø(n).
e is the public key exponent used for encryption
Now choose d, so that d · e mod ø (n) = 1, i.e., >code>d is the multiplicative inverse of e in mod ø (n)

2: Encrypting Message

Hill Cipher Program Source Codes

Messages are encrypted using the Public key generated and is known to all.

The public key is the function of both e and n i.e. {e,n}.

Hill Cipher Program Source Code Download

If M is the message(plain text), then ciphertext

3: Decrypting Message

The private key is the function of both d and n i.e {d,n}.

If C is the encrypted ciphertext, then the plain decrypted text M is

Hill Cipher Program Source Code Free

You might be wondering how to write a source code for this program.

Hill Cipher Program Source Code Example

So let’s look at the program.

Output

This is all about encryption and decryption program in C++.