Please give a short and simple explanation for the following questions.
(a) What is the certificate?
(b) Please explain the meaning of CRL (certificate revocation list).
(c) Please describe the difference of distributing public key between PGP and S/MIME.
(d) Please describe the relation between Pass Phrase Pi and Private Key KRi.
(e) Please explain why the formidable operation in InvMixColumns is not so important in AES.
(f) Please explain why DES needs 16 rounds, but not 15 or 17?
(g) How do we choose the encryption key e in RSA?
(h) What is the man-in-the-middle attack?
(i) Please explain why DES needs a 32-bit swap after 16 rounds.
(j) What is the difference of passive attack and active attack?