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Network Time Security

Network Time Security (NTS) provides cryptographic security for the client-server mode of the Network Time Protocol (NTP). This allows users to obtain time in an authenticated manner.

​​ Background

The NTS protocol is divided into two phases:

  1. NTS key exchange: Establishes the necessary key material between the NTP client and the server, using a Transport Layer Security (TLS) handshake (the same public key infrastructure as the web). Once the keys are exchanged, the TLS channel is closed and the protocol enters the second phase.
  2. NTP authentication: Authenticates NTP time syncronization packets using the results of the TLS handshake. For more information, refer to RFC 8915.

​​ Next steps

Chrony and NTPsec have support for NTS. Read the relevant documentation for guidance on setting them up to point to our time service, time.cloudflare.com.

If you would like to hear about the development of additional clients or updates on our service or would like to announce that your client supports NTS, email [email protected] to be added to our distribution list.