Arduino serial monitor gives question marks and boxes with my output - c++

Question

I am writing a program to encrypt the given input and send the cipher text over LoRa waves, but I seem to be stuck in this step.
I am using a Heltec LoRa ESP32 and have included the mbedtls library for the AES functions.
#include "mbedtls/aes.h"
#include "heltec.h"
#include <SPI.h>
#define BAND 433E6 //setting the LoRa bands to 433 mhz
mbedtls_aes_context aes;
int counter = 0;
unsigned char key[32] = "key"; // 256 bit - AES = 32 bytes for key
unsigned char iv[16];
unsigned char input [128] = "given AES plain text";
unsigned char output[128];
size_t input_len = 40;
size_t output_len = 0;
void setup() {
Heltec.begin(true /*DisplayEnable Enable*/, true /*Heltec.Heltec.Heltec.LoRa Disable*/, true /*Serial Enable*/, true /*PABOOST Enable*/, BAND /*long BAND*/);
//setup code to enable LoRa
Serial.begin(115200); //establishing serial communication with esp32 and pc
mbedtls_aes_setkey_enc( &aes, key, 256 );
mbedtls_aes_crypt_cbc( &aes, MBEDTLS_AES_ENCRYPT, 48, iv, input, output ); // AES function from mbedtls library,
}
void loop() {
Serial.print("Sending packet: ");
Serial.println(counter);
Serial.println((char*)output); //here is the issue
// send packet
LoRa.beginPacket();
LoRa.print((char*)output);
LoRa.print(counter);
LoRa.endPacket();
counter++;
delay(5000);
}
the output gives a cipher text containing (Im assuming) special characters and when I look at the Arduino serial monitor it shows bunch of reverse question marks and boxes with normal characters.
Serial.println((char*)output);
Is there a print method that can show these special characters in the Arduino IDE?