What encryption methods and data protection techniques are you familiar with?

In Java, the following methods and techniques are often used for encryption and data protection:

• Symmetric encryption (e.g., AES) — one key for encryption and decryption.
• Asymmetric encryption (e.g., RSA) — a pair of keys: public and private.
• Hashing (e.g., SHA-256) — one-way transformation of data for integrity verification.
• Digital signatures — to confirm authenticity and data integrity.
• Using Java Cryptography Architecture (JCA) and libraries such as Bouncy Castle.

Example of using AES for string encryption:

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class EncryptionExample {
    public static void main(String[] args) throws Exception {
        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
        keyGen.init(128);
        SecretKey secretKey = keyGen.generateKey();

        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);

        String text = "Hello, World!";
        byte[] encrypted = cipher.doFinal(text.getBytes());

        System.out.println("Encrypted data: " + java.util.Base64.getEncoder().encodeToString(encrypted));
    }
}