Suppose that A has obtained a certificate from certification authority X1 and B has obtained certificate authority from CA X2. A can use a chain of certificates to obtain B’s public key. In notation of X.509, this chain is represented in the correct order as –
(a) X2 X1 X1 B
(b) X1 X1 X2 A
(c) X1 X2 X2 B
(d) X1 X2 X2 A
The question was asked in a job interview.
My question is taken from Public Keys and X.509 Certificates-II topic in division Message Authentication Codes, Whirlpool Algorithm and Key Management and Distribution of Cryptograph & Network Security