The Special Fish Report
Albert W. Small (December 1944)
Codes and Ciphers
TOP SECRET Special Fish Report Page 79
In the anagramming example shown, the anagrammist had those clues
to aid him which he has marked on the worksheet.
Note that both K and Delta K are written out on the worksheet.
This worksheet was merely a convenient place to Delta the K for the
Breaking Key from Anagramming
Key obtained from the preceding anagram worksheets was broken
by the British in the following steps:
1. They made out a "Turingery" Delta K sheet. Time: 15 min.
2. They constructed Delta K1,5 Delta K 2,5 Delta K3,5
and Delta K4.5 "rectangles" and "flags of rectangles" Time: 2 men 2 1/2 hours each.
(these flags obtained by cross products of the rows? for Delta K5 patterns)
3. They combined the flags into one master flag by straight addition and
crudely converged the master flag. (If necessary, they could have
flagged the master flag.) Time: 1 man 1 hr.
4. They took the resultant Delta X5 wheel through the 4 rectangles
obtaining embryonic wheels for Delta X1 Delta X2 Delta X3 and Delta X4,
by crude convergence. Time: 1 man 1 hr.
5. They transferred the embryonic wheels to the Delta Key
"Turingery" sheet, dechi-ing on 4 impulses, and writing down the resultant
delta psi prime. Time: 1 man 3/4 hr.
6. They "counted out the Delta X wheels" (to be described).
Time: 1 man 1 1/2 hours. One counting was enough to get legal, good looking
X wheels which were immediately sent to Newmanry for setting other messages,
before the psi's had been recovered.
7. They broke the psi wheels. Time: 1 man 1 1/2 hrs.
TOTAL TIME: 1 man, 1 shift; plus 1 assistant 2 hrs.
(And I was bothering them)