Network Time Security (NTS) is a cryptographic extension for the Network Time Protocol (NTP) that authenticates time synchronization traffic. Instead of trusting every time packet on the network, NTS establishes a secure relationship between client and time server and adds protection against tampering, spoofing, and man-in-the-middle attacks. This matters because time is part of security infrastructure: logs, certificates, authentication systems, and distributed services all depend on accurate and trustworthy timestamps.
In practice, NTS is used to defend NTP against attackers who try to shift clocks, disrupt ordering, or create confusion in monitoring and incident response. It does not make time perfectly accurate, but it helps ensure that the time source being used is genuine and that packets have not been altered in transit. For defenders, NTS is a key control when hardening critical systems that need reliable synchronization over untrusted networks.