Affine Cipher Program in Java

This is a java program to implement Affine Cipher. The affine cipher is a type of monoalphabetic substitution cipher, wherein each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter. The formula used means that each letter encrypts to one other letter, and back again, meaning the cipher is essentially a standard substitution cipher with a rule governing which letter goes to which. As such, it has the weaknesses of all substitution ciphers. Each letter is enciphered with the function (ax+b)mod(26), where b is the magnitude of the shift.

Here is the source code of the Java Program to Implement Affine Cipher. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

```
 
```
```
package com.sanfoundry.setandstring;
```
```
 
```
```
import java.util.Scanner;
```
```
 
```
```
public class AffineCipher
```
```
{
```

    public static String encryptionMessage(String Msg)

```
    {
```
```
        String CTxt = "";
```
```
        int a = 3;
```
```
        int b = 6;
```

        for (int i = 0; i < Msg.length(); i++)

```
        {
```

            CTxt = CTxt + (char) ((((a * Msg.charAt(i)) + b) % 26) + 65);

```
        }
```
```
        return CTxt;
```
```
    }
```
```
 
```

    public static String decryptionMessage(String CTxt)

```
    {
```
```
        String Msg = "";
```
```
        int a = 3;
```
```
        int b = 6;
```
```
        int a_inv = 0;
```
```
        int flag = 0;
```
```
        for (int i = 0; i < 26; i++)
```
```
        {
```
```
            flag = (a * i) % 26;
```
```
            if (flag == 1)
```
```
            {
```
```
                a_inv = i;
```
```
                System.out.println(i);
```
```
            }
```
```
        }
```

        for (int i = 0; i < CTxt.length(); i++)

```
        {
```

            Msg = Msg + (char) (((a_inv * ((CTxt.charAt(i) - b)) % 26)) + 65);

```
        }
```
```
        return Msg;
```
```
    }
```
```
 
```

    public static void main(String[] args)

```
    {
```

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the message: ");

```
        String message = sc.next();
```

        System.out.println("Message is :" + message);

        System.out.println("Encrypted Message is : "

                + encryptionMessage(message));

        System.out.println("Decrypted Message is: "

                + decryptionMessage(encryptionMessage(message)));

```
        sc.close();
```
```
    }
```
```
}
```

Output:

$ javac AffineCipher.java
$ java AffineCipher
 
Enter the message: 
SANFOUNDRY
Message is :SANFOUNDRY
Encrypted Message is : VTGIJBGCSN
9
Decrypted Message is: SANFOUNDRY

Sanfoundry Global Education & Learning Series – 1000 Java Programs.

Here’s the list of Best Books in Java Programming, Data Structures and Algorithms.

« Prev - Java Program to Find the Longest Subsequence Common to All Sequences in a Set of Sequences

» Next - Java Program to Perform Cryptography using Transposition Technique

Related Posts:

Recommended Articles: