59 lines
2 KiB
Java
59 lines
2 KiB
Java
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import java.util.Scanner;
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public class App {
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public static void main(String[] args) {
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Scanner scanner = new Scanner(System.in);
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System.out.println("Enter a message to encrypt:");
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String originalMessage = scanner.nextLine();
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// Encrypt the message
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System.out.println("Enter the encryption key (an integer):");
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int encryptionKey = scanner.nextInt();
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String encryptedMessage = encrypt(originalMessage, encryptionKey);
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System.out.println("Encrypted message: " + encryptedMessage);
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// Decrypt the message
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String decryptedMessage = decrypt(encryptedMessage, encryptionKey);
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System.out.println("Decrypted message: " + decryptedMessage);
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scanner.close();
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}
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// Method to encrypt a message using Caesar cipher
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private static String encrypt(String message, int key) {
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StringBuilder encryptedText = new StringBuilder();
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for (int i = 0; i < message.length(); i++) {
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char currentChar = message.charAt(i);
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if (Character.isLetter(currentChar)) {
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char encryptedChar = (char) ((currentChar - 'A' + key) % 26 + 'A');
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encryptedText.append(encryptedChar);
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} else {
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encryptedText.append(currentChar);
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}
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}
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return encryptedText.toString();
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}
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// Method to decrypt an encrypted message using Caesar cipher
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private static String decrypt(String encryptedMessage, int key) {
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StringBuilder decryptedText = new StringBuilder();
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for (int i = 0; i < encryptedMessage.length(); i++) {
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char currentChar = encryptedMessage.charAt(i);
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if (Character.isLetter(currentChar)) {
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char decryptedChar = (char) ((currentChar - 'A' - key + 26) % 26 + 'A');
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decryptedText.append(decryptedChar);
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} else {
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decryptedText.append(currentChar);
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}
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}
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return decryptedText.toString();
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}
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}
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