#include <mbedtls/aes.h>

void encrypt(const char *plainText, const char *key, unsigned char *outputBuffer) {
  mbedtls_aes_context aes;
  mbedtls_aes_init(&aes);
  mbedtls_aes_setkey_enc(&aes, (const unsigned char*) key, strlen(key) * 8);
  mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_ENCRYPT, (const unsigned char*) plainText, outputBuffer);
  mbedtls_aes_free(&aes);
}

void decrypt(unsigned char *cipherText, const char *key, unsigned char *outputBuffer) {
  mbedtls_aes_context aes;
  mbedtls_aes_init(&aes);
  mbedtls_aes_setkey_dec(&aes, (const unsigned char*) key, strlen(key) * 8);
  mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_DECRYPT, cipherText, outputBuffer);
  mbedtls_aes_free(&aes);
}

void setup()  {
  Serial.begin(115200);  

  const char key[17] = "abcdefghijklmnop";
  const char plainText[17] = "1234567890123456";

  unsigned char cipherText[17] = {'\0'};
  unsigned char decryptedText[17] = {'\0'}; 

  encrypt(plainText, key, cipherText);
  
  Serial.print("Original plain text: ");
  Serial.println(plainText);

  Serial.print("Cipher text: ");
  for (int i = 0; i < 16; i++) 
  {
    char str[3];
    sprintf(str, "%02x", (int)cipherText[i]);
    Serial.print(str);
  }
  Serial.println();

  decrypt(cipherText, key, decryptedText); // Decrypting the cipher text

  Serial.print("Deciphered text: ");
  for (int i = 0; i < 16; i++) 
  {
    Serial.print((char)decryptedText[i]);
  }
  Serial.println();
}

void loop() {
  delay(10000);
}