 Solution

True in the intended comparison with traditional Unix protection mechanisms. Windows XP provides object-specific access control lists, subject tokens containing identities and privileges, and a security reference monitor. Rights can distinguish operations on files, registry keys, processes and other protected objects. Traditional Unix file permissions distinguish read, write and execute for owner, group and everyone else; unrestricted root authority also makes privilege separation coarse. The richer Windows XP mechanisms can express finer least-privilege policies. Cambridge's access-control notes describe this architectural contrast.

This is an architectural capability comparison, not a claim that every Windows XP installation resists attacks better than every Unix installation. More complex authorization is not itself a proof of security; configuration and implementation matter, and Unix variants can add access control lists and other protection mechanisms. Without specifying that traditional model, the blanket comparison is underspecified.