void decryptCounter(String zt){

   int length = zt.length();
   byte pole [16];

   int poc = 0;
   for(int i = 0; i < length;i=i+2){
      String pom = String(zt.charAt(i)) + String(zt.charAt(i+1));
      pole[poc] = int(hexToDec(pom));
      poc++;
   }

//      // vypis
//  for(int i= 0; i < 16; i++){
//      Serial.println(pole[i]);
//  }

  int blocks = 1;
  byte succ = aes.set_key (key, 128) ;
  succ = aes.decrypt (pole,decrypted) ;


    for (byte i = 0 ; i < blocks*N_BLOCK; i++)
    {
      byte val = decrypted[i];
      Serial.print(val>>4, HEX) ;
      Serial.print(val&15, HEX) ;
//        Serial.println(val);

    }
    Serial.println () ;


//   char hexaCounter [2 * NUMBEROFBYTES + 1];
//
//   char* myPtr = &hexaCounter[0]; //or just myPtr=charArr; but the former described it better.
//   for (byte i = 0; i < NUMBEROFBYTES; i++){
//     snprintf(myPtr,3,"%02x",decrypted[i]); //convert a byte to character string, and save 2 characters (+null) to charArr;
//     myPtr += 2; //increment the pointer by two characters in charArr so that next time the null from the previous go is overwritten.
//   }
//
////    Serial.println("Counter v HEX:");
////    Serial.println(hexaCounter);
//
//    long int retVal = hexToDec(String(hexaCounter));
//
//   return retVal;
}