I've had to sign them---use this as a guide to remind yourself not to discuss it beyond with them - then be your wonderful, fabulous self. Don't hold anything back, since they want YOUR experience, not to hear what you know about them.

If they are well-known, I would keep digging. Use sites, such as AngelList, or try asking your personal network. Also, sometimes it helps to focus on the job requirements. What experience, responsibilities, etc., did the job post ask for when you applied? Reviewing the job post can at least give you some insight to what kind of skills/person they are seeking for the role. Then prepare a few answers for the interview accordingly.

If you signed an NDA the name of the company or its parent should be on the paperwork. Hopefully you kept a copy or received a duly signed copy. Use that name and go to your state business license site to find out the names of the president, CFO, or in some cases, the legal entity behind the name. That can give you fodder for your continued search. If they do not show up in your state, do a Google search of the name, they may be registered in another state legally. Good luck!

Love this, i've definitely tried to do most of what you've shared but i'll keep digging. Thank you!

I have had to sign an NDA with an unknown company prior to an interview early in my career. I have worked mostly in startup land and in the early days of the business-side of the internet, in the late 90's, secretive interviews and NDA were commonplace of because NDA were flying around like snow flakes in a Colorado mountain town in January. If I knew the company name - then I would read every news article I could find on the company and their CEO and I tried to match my skills and successes to nuggets I find in the news articles. If I didn't know the name of the company, but I knew their industry - I found what I hoped would be a similar company and reviewed their news and product suite. If I didn't know the name of the company - then I would write out the successes in my background that would align to possible questions asked by interviews I had in the past. Basically I tried to be extra extra super prepared. Good luck!