Elementary cryptanalysis

by Helen Fouché Gaines

ENGLISH DIGRAMS

The one hundred and nine most frequent English digrams, compiled from a count of 20,000 trigrams by Fletcher Pratt, in “Secret and Urgent,” supposed not to include overlaps between words, and 5,000 by Frank R. Fraprie, including overlaps.

TH	1582		RO	275		WI	188		SA	146		CT	111
IN	784		LI	273		HO	184		NI	142		TU	108
ER	667		RI	271		TR	183		RT	142		DA	107
RE	625		IO	270		BE	181		NA	141		AM	104
AN	542		LE	263		CE	177		OL	141		CI	104
HE	542		ND	263		WH	177		EV	131		SU	102
AR	511		MA	260		LL	176		IE	129		BL	101
EN	511		SE	259		FI	175		MI	128		OF	101
TI	510		AL	246		NO	175		NG	128		BU	100
TE	492		IC	244		TO	175		PL	128
AT	440		FO	239		PE	174		IV	127
ON	420		IL	232		AS	172		PO	125
HA	420		NE	232		WA	171		CH	122
OU	361		LA	229		UR	169		EI	122
IT	356		TA	225		LO	166		AD	120
ES	343		EL	216		PA	165		SS	120
ST	340		ME	216		US	165		IL	118
OR	339		EC	214		MO	164		OS	117
NT	337		IS	211		OM	163		UL	115
HI	330		DI	210		AI	162		EM	114
EA	321		SI	210		PR	161		NS	113
VE	321		CA	202		WE	158		OT	113
CO	296		UN	201		AC	152		GE	112
DE	275		UT	189		EE	148		IR	112
RA	275		NC	188		ET	146		AV	111

INDEX

Amateurs, devices proposed by,

[132]

,

[140]

,