Get username and password
Encrypt password with MD5 or such one way encryption
Send username and encrypted password to sever
check your SQL table for their username and password combo,
if success - Login success & userdata return packets
"I also want the login to be un-jumpable with ollydbg?" - not a physically possible option? you could try like EXECryptor but nothing is truely unstoppable or you would think some of them million dollar game companies would have it by now?
If you mean to write a program to directly access an SQL table that you do not own is not possible, or far beyond the realm of anything someone having to ask would be able to do... To test the login persay of a site you didnt own, you would just examine the HTML of the login script.. and for this site you get
and then work from there to send the right data to that URL, and then check and see if your logged in - by trying to access a part of the site that is only accessible if you are logged in, such as https://guidedhacking.com/private.php
If you want to make a some-what secure login system you have to have an encryption and decryption system.
Client: will hold encryption system or function or what-ever, but not the decrypt function.
Server: will hold decryption system and encryption system.
But that doesn't make your program secure.
You should make the client depend on data from the server, so some-what core features will only work with data from the server. And that data will only be sent from the server to the client if everything is acceptable from the client (sanitize anything that looks suspicious). That way your client won't get required data for program functionality if login for example is wrong, or decryption of packages sent from client went wrong.