import java.security.*;
import javax.crypto.Cipher;
import java.util.Base64;

public class rsa {
        public static void main(String[] a) throws Exception{
                KeyPairGenerator g = KeyPairGenerator.getInstance("RSA");
                g.initialize(2048);
                KeyPair k = g.generateKeyPair();
                Cipher c = Cipher.getInstance("RSA");
                String m ="Hello, RSA!";
        
                c.init(Cipher.ENCRYPT_MODE,k.getPublic());
                String e=Base64.getEncoder().encodeToString(c.doFinal(m.getBytes()));
                System.out.println("Enc:"+e);
        
                c.init(Cipher.DECRYPT_MODE,k.getPrivate());
                System.out.println("Dec:"+new String(c.doFinal(Base64.getDecoder().decode(e))));
        }
}