#include <cstring>
#include <stdio.h>
#include <Wire.h>

#define EEPROM_I2C_ADDRESS 0x50


byte eeprom_read_byte(uint8_t i2c_device_address, uint16_t eeprom_data_address) {
  uint8_t rdata = 0xFF;
  
  Wire.beginTransmission(i2c_device_address);
  Wire.write((uint8_t)(eeprom_data_address >> 8)); //writes the MSB
  Wire.write((uint8_t)(eeprom_data_address & 0xFF)); //writes the LSB
  Wire.endTransmission();
  Wire.requestFrom(i2c_device_address,(uint8_t)1);
  if (Wire.available()) {
    rdata = Wire.read();
  }
  return rdata;
}

String eeprom_read_string(uint16_t eeprom_data_address, unsigned int size) {
  String result;
  result.reserve(size);
  for (unsigned int i = 0; i < size; ++i) {
      result.concat((char)eeprom_read_byte(EEPROM_I2C_ADDRESS, i + eeprom_data_address));
  } 

  return result;
}

void xor_str(String& str, String& key) {
    int str_len = 17;
    int key_len = key.length();
    String result = "";
    for (int i = 0; i < str_len; i++) {
        result += (char)(str.charAt(i) ^ key.charAt(i % key_len));
    }
    str = result;
}
void setup()
{
  Serial1.begin(9600);
  Wire.begin();
  String key = eeprom_read_string(0x1337, 23);
  String flag = "\x05\x03\x0f\x13\x29\x07\x09\x13\x05\x1c\x19\x13\x07\x1a\x07\x08\x13";
  xor_str(flag, key);

}

void loop()
{
    if (Serial1.available()) { // Check if there's data available on the serial port
        String input = Serial1.readStringUntil('\n'); // Read the string from the serial port
        Serial1.println(input);
        if (input == "secret_value") { // Compare the input string to the secret value
            Serial1.println("Success!"); // Print "Success!" to the serial monitor
        }
        else {
          Serial1.println("Wrong!");
        }
    }
}