Controlling servo from a webpage

Hello Everyone! Thanks for reading and any help would be appreciated! (I am fairly new to Arduino)

I am trying to make a online door lock controller which can be used to open/close the lock using a servo. I am using a Ethernet shield with my Arduino Uno and so far I am able to control the servo though a basic webpage that has two buttons to rotate the servo clockwise and counter clockwise respectively. Right now, anyone connected to my server can access the page using the default ip, and to restrict the same I was trying to add some sort of password! But I have no idea how I can do that. I was trying to find stuff online but had no luck and the stuff I did find was beyond my understanding. This is what I have right now:

#include <SPI.h>
#include <Ethernet.h>
#include <Servo.h>

Servo microservo;
int pos = 0;
byte mac = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip = { 192, 168, 1, 178 };
byte gateway = { 192, 168, 1, 1 };
byte subnet = { 255, 255, 255, 0 };
EthernetServer server(80);
String readString;

void setup() {

Serial.begin(9600);
while (!Serial) {
;
}
pinMode(led, OUTPUT);
microservo.attach(7);

Ethernet.begin(mac, ip, gateway, subnet);
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
}

void loop() {

EthernetClient client = server.available();
if (client) {
while (client.connected()) {
if (client.available()) {
char c = client.read();

//read char by char HTTP request
if (readString.length() < 100) {
//store characters to string
readString += c;
//Serial.print(c);
}

//if HTTP request has ended
if (c == ‘\n’) {
Serial.println(readString); //print to serial monitor for debuging

client.println(“HTTP/1.1 200 OK”); //send new page
client.println(“Content-Type: text/html”);
client.println();
client.println("");
client.println("");
client.println(“Class Project”);
client.println("");
client.println("");
client.println(“

Class Project

”);
client.println("
");
client.println("
“);
client.println(“

Arduino with Ethernet Shield

”);
client.println(”
“);
client.println(”
“);
client.println(”<a href="/?button2on"">Rotate Left");
client.println("<a href="/?button2off"">Rotate Right
“);
client.println(”
“);
client.println(”");
client.println("");

delay(1);
//stopping client
client.stop();
}
if (readString.indexOf("?button2on") >0){
for(pos = 0; pos < 180; pos += 3)
{
microservo.write(pos);
delay(15);
}
}
if (readString.indexOf("?button2off") >0){
for(pos = 180; pos>=1; pos-=3)
{
microservo.write(pos);
delay(15);
}
}
//clearing string for next read
readString="";

}
}
}
}
}