Appendix G: Exercises - Codes: The Guide to Secrecy from Ancient to Modern Times - page 584

5.28. Let t =5, p = 9001, ( c 1 ,c 2 ,c 3 ,c 4 ,c 5 ) = (2706 , 3743 , 95 , 3239 , 6475), and,

( n (1 1 ,n (1 2 ,n (1 3 ,n (1) ) = (217 , 1 , 3549 , 2);

4

( n (2 1 ,n (2 2 ,n (2 3 ,n (2)

4 ) = (900 , 25 , 867 , 27);
( n (3 1 ,n (3 2 ,n (3 3 ,n (3 4 ) = (1002 , 111 , 257 , 29);
( n (4 1 ,n (4 2 ,n (4 3 ,n (4) )=(1 , 261 , 69 , 96);

4

( n (5 1 ,n (5 2 ,n (5 3 ,n (5)

)=(2 , 900 , 8999 , 21) .

4

5.29. Construct a multiauthority election protocol that extends the notions
described on pages 216 and 217 by allowing the independent choice of
more than one generator of

.
( Hint: Allow each voter to encrypt their vote with respect to all the gen-
erators such that exactly one of the encipherings reveals the actual vote,
by an interactive proof of knowledge, say. )

Z /q Z

5.30. Explain how SSL/TLS described in Section 5.7 on pages 218-226, is
susceptible to Eve's doing a tra 7 c analysis on the communications. In
other words, explain how Eve may use her observations concerning the
number of messages being sent to and from a specific Internet address to
extract information, even if she does not know the particular content of
those messages.
( Hint: Assume you are a lawyer ( just for this one time ) , and you want
to know about the legal activities of competing law firms in terms of the
volume of their activity. ( Also, see Footnote 8.11 on page 309. ))

5.31. Outline the mechanism for the use of different coin denominations via
differing RSA exponents mentioned on page 231 of Section 5.8 on digital
cash.

G.6 Chapter 6 Exercises

Exercises 6.1-6.8 refer to the Blom key predistribution protocol presented
on pages 234-236. Assuming, as we did in Example 6.1 on page 235,
that there is a network of only three users, use the parameters given to
determine the keys k AB , k AC , and k BC .

6.1. p = 1297, ( r 1 ,r 2 ,r 3 ) = (12 , 79 , 721), ( u A ,u B ,u C ) = (92 , 219 , 691).

6.2. p = 2843, ( r 1 ,r 2 ,r 3 ) = (29 , 289 , 378), ( u A ,u B ,u C ) = (919 , 1001 , 2004).

6.3. p = 3253, ( r 1 ,r 2 ,r 3 ) = (38 , 391 , 499), ( u A ,u B ,u C ) = (111 , 1111 , 2000).