Cryptology - Unofficial St. Mary's College of California Web Site

9.7. EXERCISES 187
The rules that Wheatstone used to encipher his messages are a bit different
than the ones we use. Can you figure them out Hint: consider Playfair’s
name for this cipher.
21. Another way to use Playfair is construct a 6 × 6 square that consists of
the 26 letters followed by the 10 numbers 0, 1, ..., 9. Then encipher and
decipher as usual. (Below we use z as the double-breaking letter, rather
than x. I’ve also used o for the letter “O”, to prevent confusion with the
number 0.)
(a) Encipher 1800 Pennsylvannia Avenue.
(b) Encipher The Lodge, the residence of the Australian Prime Minister.
(c) Decipher INWBG RBSoM TUo0.
(d) Decipher FHBCM LPVWA.
(e) Decipher 76CPT QHo HTXNB 2BW.
(f) Decipher Y8Y0T YWAVF oLWD.
22. During World War II there was a widespread network of Australian coastwatchers
spread about on the numerous island in the South Pacific. [Kahn,
pages 591–3.]
They observed enemy activity from the peaks and cliffs of enemy-held
islands, collected bits of information from native allies, and radioed
their information to Allied military commands. They frequently gave
valuable early warning of Japanese bombing raids and ship movements,
and they assisted in the rescue of downed Allied airmen.
In the early morning hours of August 2, 1943, coast-watcher Lieutenant
Arthur Reginald Evans of the Royal Australian Naval Volunteer
Reserve saw a pinpoint of flame on the dark waters of Blackett
Strait from his jungle ridge on Kolombangara Island, one of the
Solomons. He did not know then that the Japanese destroyer Amagiri
had rammed and sliced in half an American patrol torpedo boat,
PT 109, lieutenant John F. Kennedy, United States Naval Reserve,
commanding. But at 9:30 that morning he received
the following message:
(a) KXJEY UREBE ZWEHE WRYTU HEYFS KREHE GOYFI WTTTU OLKSY CAJPO
BOTEI ZONTX BYBWT GONEY CUZWR GDSON SXBOU YWRHE BAAHY USEDQ
The keyword is Royal new zealand navy. What does it say
(b) Evan reported back that Object still floating between Meresu and
Gizo, and was told later that there was a possibility that survivors
landing either Vangavanga or islands. In fact, Kennedy had led his
men to Plum Pudding Island. This was behind enemy lines, and only
3 or 4 miles from Gizo Island where there was a Japanese garrison.