Reply to post: Re: Time NTP was upgraded(See what I did there!)

Boffins want to stop Network Time Protocol's time-travelling exploits

Anonymous Coward
Anonymous Coward

Re: Time NTP was upgraded(See what I did there!)

And how reliable are GPS and radio clocks? I seem to remember reading a detailed description once of the signal used by radio clocks and seeing no mention of cryptographic authentication, so that would presumably be easy to fake. I don't know about GPS. Can anyone tell us?

Another thing about GPS: it doesn't use UTC, does it? So you'd have to, firstly, make sure your systems don't fail when there's a genuine leap second, and, secondly, make sure an adversary doesn't feed you bogus information about leap seconds.

The next version of NTP should make it easier to get TAI and UTC in a straightforward way from the same server, rather than have to work one out from the other using a document taken from a different server. The clock_gettime system call on Linux lets you ask for TAI and UTC, but very few systems seem to be set up so that this works properly. (Go on, try it!)

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