[time-nuts] On the IETF leap-seconds.list SHA1

[Mike Cook]

> Le 20 déc. 2017 à 12:51, Anders Wallin <anders.e.e.wallin at gmail.com> a écrit :
> 
> Hi all,
> So I'm doing the typical Wednesday thing you might do, that is writing a
> small script for checking the SHA1 checksum in leap-seconds.list files.
> I came up with [1] which produces output [2].
> 
> For the Paris Observatory and USNO files my program agrees with the SHA1s
> in the files.
> For the IETF file there seems to be one byte, a "0" at the start of the
> third group of 8 hex characters missing.
> 
> This is somewhat funny/alarming, since the IETF leap-seconds.list is the
> first thing that shows up (at least for me) on google when looking for
> leap-seocnds.list.

   This is not a bug but a « feature ». From the ntpd leap hash checking code:

 * The NIST code creating the hash writes them out as 5 hex integers
 * without leading zeros. 

   Still, it a little unorthodox and complicates the code.
  
> 
> Please do add to and improve on my code on github - if this is your sort of
> thing ;)
> 
> happy holidays!
> Anders
> 
> [1]
> https://github.com/aewallin/leap-seconds.list_sha1_check/blob/master/leap_sha.py
> [2]
> https://github.com/aewallin/leap-seconds.list_sha1_check/blob/master/output.txt
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