Get the Roughtime

The “Hello, world!” of Roughtime is very simple: the client sends a request over UDP to the server and the server responds with a signed timestamp.

You just need the server’s address and public key to run the protocol:

• Server address: roughtime.cloudflare.com:2002 (resolves to an IP address in our anycast IP range Open external link ). You can use either IPv4 or IPv6.
• Public key: gD63hSj3ScS+wuOeGrubXlq35N1c5Lby/S+T7MNTjxo=

To get started, download and run Cloudflare’s Go client Open external link :

go get -u github.com/cloudflare/roughtime
go install github.com/cloudflare/roughtime...
getroughtime -ping roughtime.cloudflare.com:2002 -pubkey gD63hSj3ScS+wuOeGrubXlq35N1c5Lby/S+T7MNTjxo=

​​ Beta notice

Cloudflare Roughtime is currently in beta. As such, our root public key may change in the future. We will keep this page up-to-date with the most current public key.

You can also obtain it programmatically using DNS. For example:

$ dig TXT roughtime.cloudflare.com | grep -oP 'TXT\s"\K.*?(?=")'

​​ Next steps

Beyond just getting the Roughtime from Cloudflare, you may want to use it to keep your clock in sync.