Impossible travel time is a policy that detects and blocks login attempts from locations that are geographically impossible to reach from the previous login location within a certain time frame. For example, if a user logs in from New York and then tries to log in from Tokyo within an hour, the policy would flag this as impossible travel time and disable the account. This policy helps prevent unauthorized access from compromised credentials or attackers using proxy servers. Reference: 1 CompTIA Security+ Certification Exam Objectives, page 6, Domain 1.0: Attacks, Threats, and Vulnerabilities, Objective 1.2: Compare and contrast different types of social engineering techniques 2 CompTIA Security+ Certification Exam Objectives, page 14, Domain 3.0: Implementation, Objective 3.4: Implement identity and account management controls 3 https://docs.microsoft.com/en-us/azure/active-directory/identity-protection/howto-sign-in-risk-policy#impossible-travel

A digital certificate is an electronic document that contains the public key and identity information of an entity, such as a person, organization, website, etc. It is issued and signed by a trusted authority called a certificate authority (CA). It can provide non-repudiation by proving the identity and authenticity of the sender and verifying the integrity of the message or data.

A turnstile is a physical security control that regulates the entry and exit of people into a facility or an area. It can prevent unauthorized access, tailgating, etc., by requiring valid credentials or tokens to pass through

Input sanitization can help prevent attackers from learning the service account name by removing potentially harmful characters from user input, reducing the likelihood of successful injection attacks. Reference:
CompTIA Security+ Certification Exam Objectives 2.2: Given a scenario, implement secure coding techniques.
CompTIA Security+ Study Guide, Sixth Edition, pages 72-73

An internet proxy is a server that acts as an intermediary between a client and a destination server on the internet. It can restrict web access and monitor the websites that employees visit by filtering the requests and responses based on predefined rules and policies, and logging the traffic and activities for auditing purposes