Re: [Ntp] NTP Security (was NTPv5: big picture)

[FUSTE Emmanuel <[e-mail]>]

Le 22/01/2021 à 03:34, Philip Prindeville a écrit :
>
>> On Jan 19, 2021, at 5:24 AM, Magnus Danielson <[e-mail]> wrote:
>>
>>> I think the point is that you cannot bootstrap secure time out of
>>> nothing.
>> That's a conjecture, yet to be proven.
>
> No, that's basic Information Theory.  Lost or non-existent information can't be recreated from a void.
Exactly. And here the information is present/existent in a lot 
of/multiple source.
As there is a possibility that some are compromised and your must sort 
out/validate them.
Depending of your needs, you could startup with pretty low known 
validation materials with very good confidence, up to multiple 
cryptographic factors and less than a second away trusted local time and 
very very high confidence.
Look at today real world status  ! This is terrific, more than 99.9% of 
devices, phone, computers, wifi routers, etc ... using NTP even with 
local RTC blindly trust ANY ntp source without any validation procedure 
/ validation material and only rely on NTP algorithms to try to sort the 
sources, on the better implementations.

Emmanuel.