Encrypting text with RSA and RSA/ECB/PKCS1Padding in Java

 Following java code can be used to encrypt a message with RSA and RSA/ECB/PKCS1Padding.

import javax.crypto.Cipher;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.util.Base64;

public class RSAEncryptionTest {

    private PrivateKey privateKey;
    private PublicKey publicKey;

    public RSAEncryptionTest() {
        try {
            KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
            generator.initialize(1024);
            KeyPair pair = generator.generateKeyPair();
            privateKey = pair.getPrivate();
            publicKey = pair.getPublic();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public String encrypt(String message) throws Exception{
        byte[] messageToBytes = message.getBytes();
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.ENCRYPT_MODE,publicKey);
        byte[] encryptedBytes = cipher.doFinal(messageToBytes);
        return encode(encryptedBytes);
    }
    private String encode(byte[] data){
        return Base64.getEncoder().encodeToString(data);
    }

    public String decrypt(String encryptedMessage) throws Exception{
        byte[] encryptedBytes = decode(encryptedMessage);
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE,privateKey);
        byte[] decryptedMessage = cipher.doFinal(encryptedBytes);
        return new String(decryptedMessage,"UTF8");
    }
    private byte[] decode(String data){
        return Base64.getDecoder().decode(data);
    }

    public static void main(String[] args) {
        RSAEncryptionTest rsa = new RSAEncryptionTest();
        try{
            String encryptedMessage = rsa.encrypt("Hello World");
            String decryptedMessage = rsa.decrypt(encryptedMessage);

            System.out.println("Encrypted: "+encryptedMessage);
            System.out.println("Decrypted: "+decryptedMessage);
        } catch (Exception e){
            e.printStackTrace();
        }
    }
}

Output

Encrypted: RMMIeSHL7I4sTP5gIwm1SJ9MWYFwHH3uauM7fdzd59mskZMxMDhBYkfhE7/qOz6FPxKMd1Fwvb9JY2P4+31Rgidt3n9pQMpd/Be6gLAfuxxGhpE2Ytt7pKePyzUziUZRSg/C8ygkVF4+LcXU36xE/+JMSXAwd3D4fRq3HGs4wdY=

Decrypted: Hello World