CAESAR CIPHER
Generate the Caesar cipher text of given plain text and also decrypt the generated cipher text.
Also give the user the facility to change the value of key.
Testing Data
Encryption Plain Text
:- meet me after the toga party
Cipher Text
:- PHHW PH DIWHU WKH WRJD WRJD SDUWB ( n = 3)
Decryption Cipher Text
: khoor eurwkhu
Plain Text
: HELLO BROTHER
import java.util.*; class CeasarCipher { public static void findPlainText() { String letter[] = {"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" }; String plainText="", cipherTxt; System.out.println("Enter a ciphertext"); Scanner in = new Scanner(System.in); cipherTxt = in.nextLine(); int index = 0; for(int i=0; i
{ index = j;break;}}if(index < 3) {
index = (25 - index); plainText = plainText + letter[index]; } else { plainText = plainText + letter[index - 3];}}} System.out.println("Plain text of "+cipherTxt+" is "+ plainText); }
public static void findCeaserCipher() { String letter[] = {"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" }; String plainText, cipherTxt = ""; System.out.println("Enter a plaintext"); Scanner in = new Scanner(System.in);plainText = in.nextLine(); int index = 0;for(int i=0; i
String val = String.valueOf(c); if(val.equals(" ")) { cipherTxt = cipherTxt + " ";} else { for(int j=0; j
22) { index = (index + 3) % 26; cipherTxt = cipherTxt + letter[index]; } else { cipherTxt = cipherTxt + letter[index + 3]; } }
} System.out.println("Cipher text of "+plainText+" is "+ cipherTxt); }
public static void main (String[] args) { Scanner in = new Scanner(System.in); System.out.println("Enter the choice:"); System.out.println("1. Plain text to cipher text."); System.out.println("2. cipher text to plain text."); int choice = in.nextInt();switch(choice) { case 1:findCeaserCipher(); break; case 2:findPlainText(); break; default:System.out.printf("Invalide Choice"); break;} } }
OUTPUT
meet me after the toga party
khoor eurwkhu
