#include "Arduino.h"
#include "mbedtls/aes.h"
 
void setup() {
  Serial.begin(115200);

  //data= "Only 16character"
  const char *hexString = "4933ad56f64319b32e027bce6338bd76";
  unsigned char encrypted[16];

  hexStringToByteArray(hexString, encrypted);

  // Serial.println("Encrypted array:");
  // Serial.print("{");
  // for (int i = 0; i < 16; i++) {
  //   Serial.printf("0x%02x", encrypted[i]);
  //   if (i < 15) {
  //     Serial.print(", ");
  //   }
  // }
  // Serial.println("};");

  char * key = "abcdefghijklmnop";
 
  unsigned char decrypted[16];

  mbedtls_aes_context aes;
  mbedtls_aes_init(&aes);
  mbedtls_aes_setkey_dec(&aes, (const unsigned char*) key, strlen(key) * 8); // Set decryption key

  // Decrypt the first block
  mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_DECRYPT, encrypted, decrypted);
  Serial.println("Decrypted block 1:");
  for (int i = 0; i < 16; i++) {
    Serial.print((char)decrypted[i]);
  }
  Serial.println();

  mbedtls_aes_free(&aes);
}

void loop() {}

void hexStringToByteArray(const char *hexString, unsigned char *byteArray) {
  for (int i = 0; i < 16; i++) {
    sscanf(hexString + 2 * i, "%2hhx", &byteArray[i]);
  }
}