- [3] [[X.400]]
-- [5] [CITE@en[[[RFC 987]] - Mapping between X.400 and RFC 822]], [TIME[2021-01-31T12:05:01.000Z]], [TIME[2021-03-13T07:30:36.509Z]] <https://tools.ietf.org/html/rfc987#page-20>
-- [4] [CITE@en[[[RFC 1138]] - Mapping between X.400(1988) / ISO 10021 and RFC 822]], [TIME[2021-01-31T11:41:52.000Z]], [TIME[2021-03-13T07:30:03.706Z]] <https://tools.ietf.org/html/rfc1138#section-3.3.5>
-- [6] [CITE@en[RFC 1148 - Mapping between X.400(1988) / ISO 10021 and RFC 822]], [TIME[2021-02-21T20:28:49.000Z]], [TIME[2021-03-13T07:35:42.733Z]] <https://tools.ietf.org/html/rfc1148#section-3.3.5>
-- [7] [CITE@en[RFC 1327 - Mapping between X.400(1988) / ISO 10021 and RFC 822]], [TIME[2021-02-21T20:58:05.000Z]], [TIME[2021-03-13T09:42:54.093Z]] <https://tools.ietf.org/html/rfc1327#section-3.3.5>
-- [8] [CITE@en[RFC 2156 - MIXER (Mime Internet X.400 Enhanced Relay): Mapping between X.400 and RFC 822/MIME]], [TIME[2021-03-14T09:07:09.000Z]], [TIME[2021-03-23T12:26:00.379Z]] <https://tools.ietf.org/html/rfc2156#section-3.3.5>


[1] [CITE@en[RFC 5280 - Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile]]
([TIME[2015-02-22 15:44:10 +09:00]] 版)
<http://tools.ietf.org/html/rfc5280#section-4.1.2.5.1>

[2] [CITE@en[RFC 4517 - Lightweight Directory Access Protocol (LDAP): Syntaxes and Matching Rules]]
([TIME[2015-03-08 19:15:43 +09:00]] 版)
<http://tools.ietf.org/html/rfc4517#section-3.3.34>

[9] [CITE@en[rfc3852]], [TIME[2021-07-05T05:43:04.000Z]] <https://datatracker.ietf.org/doc/html/rfc3852#section-11.3>


[FIG(quote)[
[FIGCAPTION[
[12] [CITE@en[RFC 5280 - Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile]]
([TIME[2015-02-22 15:44:10 +09:00]] 版)
<http://tools.ietf.org/html/rfc5280#section-4.1.2.5.1>
]FIGCAPTION]

>  Conforming
systems MUST interpret the year field (YY) as follows:
>       Where YY is greater than or equal to 50, the year SHALL be
interpreted as 19YY; and
>       Where YY is less than 50, the year SHALL be interpreted as 20YY.

]FIG]