Galois/Counter Mode java encryption example 30.01.23

Full round, encrypt the text "hello world" and decrypt it

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Gcm
{
    public static final int AES_KEY_SIZE = 128;
    public static final int GCM_IV_LENGTH = 12;
    public static final int GCM_TAG_LENGTH = 16;

public static void main(String[] args) throws Exception
    {
	String data = "hello world";
	byte[] data_byte = data.getBytes();
        String password = "12345";
	byte[] password_byte = new byte[]{49, 50, 51, 52, 53, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
        //for(byte b:password_byte)
        //  System.out.println(b);
	
        System.out.println("data : " + data);
        System.out.println("password : " + password);

byte[] iv = new byte[GCM_IV_LENGTH];
        SecureRandom random = new SecureRandom();	
        random.nextBytes(iv);		
        //for(byte b:iv)
        //  System.out.println(b);
	
        GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(GCM_TAG_LENGTH * 8, iv);
        SecretKeySpec keySpec = new SecretKeySpec(password_byte, "AES");
	
        Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, gcmParameterSpec);
        byte[] ct = cipher.doFinal(data_byte);
        //for(byte b:ct)
        //  System.out.println(b);

cipher.init(Cipher.DECRYPT_MODE, keySpec, gcmParameterSpec);
        byte[] bt = cipher.doFinal(ct);
	String text =  new String(bt);
        System.out.println("Text : " + text);
    }

}

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Galois/Counter Mode java encryption example 30.01.23

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