Have a problem when encrypt by RSA !!!

Question

I have a method
public static byte[] EncryptByPublicKey(byte[] text, PublicKey key) {
        //byte[] encryptText = null;
        try {
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            return cipher.doFinal(text);
        catch (Exception e){
            System.out.println("Err " + e.toString());
        return null;
    }I write a class test this method
public static void main(String[] args){
        PublicKey pub = ReadPublicKey("publicReceiver.k");
        String message = "abc";
        String encryptText =
                    new String(EncryptByPublicKey(message.getBytes(), pub));
        System.out.println(encryptText);
    }when I execute the minutes each are different results for each.
help me please, thanks a lot of

Answer 1

PKCS1 padding in encryption mode uses random bytes for the padding so you should pretty much always get a different resultant encrypted result.
Note - the bytes of the ciphertext should never be turned into readable text using new String(ciphertext) since one cannot guarantee that all bytes and byte sequences are valid for your default character encoding. Use Base64 or Hex encoding.