The following compilation represents what facet of cryptanalysis? A 8.2 B 1.5 C 2.8 D 4.3 E 12.7 F 2.2
G 2.0 H 6.1 I 7.0 J 0.2 K 0.8 L 4.0 M 2.4 N 6.7 O 7.5 P 1.9 Q 0.1 R 6.0 S 6.3 T 9.1 U 2.8 V 1.0 W 2.4 X 0.2
Y 2.0 Z 0.1

A.
Frequency analysis

B.
Cilly analysis

C.
Cartouche analysis

D.
Period analysis

Explanation:
The compilation is from a study by h. Becker and f. Piper that was originally published in Cipher
Systems: The Protection of Communication. The listing shows the relative frequency in percent of
the appearance of the letters of the English alphabet in large numbers of passages taken from

newspapers and novels. Thus, in a substitution cipher, an analysis of the frequency of appearance of
certain letters may give clues to the actual letter before transformation. Note that the letters E, A,
and T have relatively high percentages of appearance in English text. *Answer “Period analysis”
refers to a cryptanalysis that is looking for sequences that repeat themselves and for the spacing
between repetitions. This approach is used to break the VigenËre cipher. * Answer “Cilly analysis” is
a reference to a cilly, which was a three-character message key used in the German Enigma machine.
* In answer “Cartouche analysis”, a cartouche is a set of hieroglyphs surrounded by a loop. A
cartouche referring to King Ptolemy was found on the Rosetta Stone.