How to protect the form with a custom code?

Can I create a form that only a certain customer can access?  I would like a certain customer to be able to order from a specific form but keep other customers from being able to utilize it.  Is there a way to create a form that has a logon required to use it?  Thanks in advance for your help and assistance.

So far there is not a way to password protect a form, but you can hide the fields in your form and still ask for some code to get the fields and submit the form, then if the entered code is correct show the fields so your customer can fill the form. 

For example, you should add a Text Box field at the very top of your form followed by all the other fields that you need in your form: 

Then you need to add the condition to show the fields if the entered word is correct: 

But, please avoid to use words like password, passcode or similar, otherwise your account may be suspended because of phishing suspicious. 

Here is also a guide that will provide you more details about showing or hiding fields based on other fields input / selection: How-to-Show-or-Hide-Fields-Base-on-User-s-Answer

Hope this helps.