(a) How does the main security aim of the Clark-Wilson model differ from that of the Bell-LaPadula model? (b) Consider the following documents that have been created within the Bell-LaPadula security model. The levels are: top secret (ts), secret (s), confidential (c), and unclassified (uc). In addition to these levels, there are the following categories: development (D), production code (PC), and software tools (T) Document 1: c, {D, T} Document 2: s, {T, PC} Document 3: ts, { } Document 4: uc, {D, T, PC} Alice has...