# -=*( This file is in the public domain )*=- # This NTP leapsecond file was created with data obtained from # the United States Naval Observatory (USNO) MAIA FTP server. # # Find it at: # Updated using information from IERS Bulletin C 57 (7 Jan 2019) # Found at # # # It should be noted that this bulletin states there will be no # leap-second 1 July 2019. Thus only the file expiry has changed. # # This file is not a forgery, per se, but it is created # by some one/thing other than a national metrology lab. # It is necessitated by a current US government shutdown # and the resulting lack of an NIST generated file. # # UTC is a time scale based upon standard international (SI) # seconds and derived from Temps Atomique International (TAI). # # Leap seconds are an official correction to UTC to keep it # within 0.9 seconds of UT1; yet another time standard # based upon the orientation of the earth in space. # # These data, kept in "leap-seconds.list", are used by the # Network Time Protocol daemon (NTPd) to determine when to # apply leap seconds to Coordinated Universal Time (UTC). # "leap-seconds.list" is a symbolic link to the actual # file name, leap-seconds.xxxxxxxxxx, where xxxxxxxxxx # is derived from the NTP update timestamp (below). # # Theoretically, a leap second may be positive or negative. # Realistically, negative leap seconds are unlikely to occur. # # All timestamps in this leap seconds file are encoded using the # NTP epoch. These timestamps represent the number of seconds # since 1 Jan 1900 0:00:00. This is Modified Julian Date (MJD) # 15020 and Julian Date 2415020.5. There will be an unsigned # 32-bit overflow to the second NTP era in 2036 (07 Feb 2036 # 06:28:16 UTC to be precise). # # A leap second datum consists of an NTP timestamp and the # number of seconds difference between TAI and UTC (e.g. # currently TAI-UTC is 37). UTC was established at midnight on # 1 Jan 1972 with TAI-UTC started at 10. There was no mechanism # prior to that time defining when to apply leap seconds. # # Note: the first datum in the leap-seconds.list file is *not* # a leap-second; it denotes the definition of the UTC timescale. # # Leap-seconds rules are establish in: # # International Telecommunications Union-Regulation (ITU-R) # 460-6, Annex 1, Section 2. # # # # NTP Leap second files have an update time (#$). This is often # the UTC zero (0) hour time of the day when the leap second file # is built. It should be updated whenever a new IERS Bulletin C # is issued. # #$ 3755808000 # # Leap second data have a lifetime. Traditionally, this ends on # the twenty-eighth (28) day of the month six months after the # period of time described in the latest IERS Bulletin C. This # is the expiry time (#@). # #@ 3786480000 # # Leap second files have a hash, as define in NIST's FIPS 180 # Secure Hash Standard (SHS), current revision 4 (FIPS 180-4). # # FIPS Publications: # Direct Link: # # It is based on an SHA[1] digest, created using the data # portions of the file including leap second data and the update # and expiry timestamps. All "white space" and comments are # excluded in the computation thereof. The 160-bit SHA[1] # digest polynomial are encoded in five hexadecimal grouping at # the end of the file (#h). The hash itself is NOT included in # the SHA[1]. It can also be calculated using GNU sha1sum which # generates the same 160-bit digest, given the same data, in # forty hexadecimal characters. # # NTP delta #timestamp T Date of Change # 2272060800 10 # 1 Jan 1972 (MJD 41317) 2287785600 11 # 1 Jul 1972 (MJD 41499) 2303683200 12 # 1 Jan 1973 (MJD 41683) 2335219200 13 # 1 Jan 1974 (MJD 42048) 2366755200 14 # 1 Jan 1975 (MJD 42413) 2398291200 15 # 1 Jan 1976 (MJD 42778) 2429913600 16 # 1 Jan 1977 (MJD 43144) 2461449600 17 # 1 Jan 1978 (MJD 43509) 2492985600 18 # 1 Jan 1979 (MJD 43874) 2524521600 19 # 1 Jan 1980 (MJD 44239) 2571782400 20 # 1 Jul 1981 (MJD 44786) 2603318400 21 # 1 Jul 1982 (MJD 45151) 2634854400 22 # 1 Jul 1983 (MJD 45516) 2698012800 23 # 1 Jul 1985 (MJD 46247) 2776982400 24 # 1 Jan 1988 (MJD 47161) 2840140800 25 # 1 Jan 1990 (MJD 47892) 2871676800 26 # 1 Jan 1991 (MJD 48257) 2918937600 27 # 1 Jul 1992 (MJD 48804) 2950473600 28 # 1 Jul 1993 (MJD 49169) 2982009600 29 # 1 Jul 1994 (MJD 49534) 3029443200 30 # 1 Jan 1996 (MJD 50083) 3076704000 31 # 1 Jul 1997 (MJD 50630) 3124137600 32 # 1 Jan 1999 (MJD 51179) 3345062400 33 # 1 Jan 2006 (MJD 53736) 3439756800 34 # 1 Jan 2009 (MJD 54832) 3550089600 35 # 1 Jul 2012 (MJD 56109) 3644697600 36 # 1 Jul 2015 (MJD 57204) 3692217600 37 # 1 Jan 2017 (MJD 57754) # #h ffee5390 2e3cf253 e15b646e 01768a18 e83785c3