Cryptography Reference
In-Depth Information
Appendix G: Exercises
We do not see things as they are, but as we are.
— from The Talmud, compilations of Jewish civil ceremonial law, dating
from the fifth century AD.
G.1 Chapter 1 Exercises
In Exercises 1.1-1.4, use Table 1.2 for the Caesar cipher on page 11 to
decrypt the ciphertext given in each.
1.1. ZH EHJLO RXV MRXUQB .
1.2. RQ WKH LVODQG RI FUHWH .
1.3. ZLWK WKH PLQRDQ FLYLOLCDWLRQ .
1.4. D WUXOB PDJQLILFHQW SHRSOH .
In Exercises 1.5-1.8, use Table 1.3 on page 11 to decrypt the numeric ci-
phertext given in each.
1.5. 20 , 18 , 4 , 12 , 14 , 3 , 20 , 11 , 0 , 17 , 0 , 17 , 8 , 19 , 7 , 12 , 4 , 19 , 8 , 2 .
1.6. 11 , 8 , 13 , 4 , 0 , 17 , 0 , 17 , 0 , 8 , 18 , 0 , 12 , 24 , 18 , 19 , 4 , 17 , 24 .
1.7. 4 , 0 , 18 , 19 , 4 , 17 , 8 , 18 , 11 , 0 , 13 , 3 , 8 , 18 ,
17 , 8 , 2 , 7 , 8 , 13 , 7 , 8 , 18 , 19 , 14 , 17 , 24 .
1.8. 3 , 4 , 2 , 8 , 15 , 7 , 4 , 17 , 19 , 7 , 4 , 15 , 7 , 0 , 8 , 18 , 19 , 14 , 18 , 3 , 8 , 18 , 10 .
In Exercises 1.9-1.12, use the Polybius square 1.1 on page 10 to decrypt the
numeric ciphertext given in each.
1.9. 3534315412244543 521143 1123151114 3421 232443 44243215 .
1.10. 253334132543 4215353111131514 44344213231543 .
1.11. 44454233243322 142422244443 24334434 433445331443 .
1.12.
33345224442443
11
1211432443
3421
32113354
13243523154243 .
1.13. Using the permutation cipher displayed on page 9 decrypt the following
ciphertext:
IPEROTEWMURDS .
( Hint: See the discussion concerning the finding of inverse permutations
on page 122. )
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