Which of the following standards concerns digital certificates?
A.
X.400
B.
X.25
C.
X.509
D.
X.75
Explanation:
X.509 specifies standard formats for public key certificates and attribute certificates, which are digital
certificates.
Incorrect Answers:
A: X.400 is a group of ITU-T Recommendations that define standards for Data Communication Networks for
email.
B: X.25 is an ITU-T standard protocol suite for packet switched wide area network (WAN) communication.
C: X.75 is an International Telecommunication Union (ITU) standard that specifies the interface for
interconnecting two X.25 networks.Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, pp. 833
https://en.wikipedia.org/wiki/X.509
https://en.wikipedia.org/wiki/X.400
https://en.wikipedia.org/wiki/X.25
https://en.wikipedia.org/wiki/X.75