Physical access control at Google offices: balancing security and daily convenience

You are a product manager at Google, asked to design the badge system that controls who can enter Google's office buildings and the spaces inside them. Decide whose needs it has to serve, identify the problems worth solving, choose what to build first, and explain how you would judge whether it works. ```hint Two customers at one door The security team needs to keep the wrong people out and know who went where; the people walking through the door every day mostly want not to notice it. Look for designs that serve both instead of trading one away. ``` ### Clarifying Questions - Who must the system cover: only full-time employees, or also contractors, vendors, visitors and delivery staff? - Does the badge have to be a physical card, or can a phone, a watch or biometrics serve as the credential? - Should it handle uses beyond opening doors, such as elevators, printers, lockers or paying for things on campus? - Is this for a single campus or every office worldwide, with different local privacy laws and building rules? ### What a Strong Answer Covers - A goal that balances keeping unauthorized people out with low friction for authorized people, plus a clear stance on the privacy of entry logs and biometric data. - A map of the people involved (badge holders, visitors and their hosts, security operations, HR and facilities) and a reasoned choice of whose problems to solve first. - Concrete features across the whole access lifecycle: granting access, daily entry, restricted areas, lost badges, and removing access when someone leaves. - Failure handling for tailgating, copied or lost credentials, network or power outages, and emergency evacuation. - Success metrics for both security and convenience, with guardrails. ### Follow-up Questions - An employee is let go on a Friday afternoon. Walk through how their building access ends and how you would know it worked. - Security wants turnstiles in every lobby to stop tailgating, and employees say mornings will get slower. How do you decide? - Would you let employees enter with face recognition instead of a badge? What would need to be true first?