$($a$)$ Security is of paramount concern when using multi$-$user systems. Briefly

explain the following security issues that arise in a multi$-$user system:

$($i$)$ authentication of users.

$($ii$)$ user privileges.

$($iii$)$ confidentiality of data.

$($b$)$ Discuss FOUR $(4)$ techniques and precautions that can be used when

$($i$)$ allowing users to connect to the database.

marks$)$

$($ii$)$ authorizing users to perform certain actions within the database.

$(4$ marks$)$

$($c$)$ Explain the effect of the following SQL statements when executed by a user

called Amy. Employees is a table owned by a user called Amy.

GRANT CREATE VIEW TO JOE, FRED;

REVOKE DELETE ON employees FROM JOE;

$(5$ marks$)$

$($d$)$ Specify THREE $(3)$ ways of how the Secure Sockets Layer and Secure HTTP

provide the security mechanism.

$(6$ marks$)$