[tor-talk] How accurate does need the clock to be?

[proper at tormail.net]

> On 02/19/2012 02:17 PM, proper at tormail.net wrote:
>> Let's assume the time server is not trusted.
>>
>> How accurate does the clock have to be? Is +/- 30 minutes sufficient for
>> Tor's correct operation? Do you see any risks if the user manually
>> adjusts
>> the clock on each restart?
>>
>
> Why would you be doing this?

Battery defect (hardware clock gets reset after poweroff), hardware clock
defect, clock is obviously wrong at boot and the wrist/mobile watch is
also only about +/- 5 minutes accurate, usage in live cd's or virtual
machines, if one does not trust the operating systems unencrypted NTP.

There are many reasons, hopefully it's not required to agree on valid
reasons to get an answer. Right now most people use the unencrypted NTP
and it's accuracy seams to fit for Tor. I searched a lot but found only
the information "correct clock is important for Tor". But the question
remains...

How accurate does the clock have to be for Tor's correct operation?