Then A=11 or 41, J=10 or 40 and T=20 or 50 as we found. Using the above alphabet, the message may easily be read. Note that this cipher is made up of ten characters only, the Arabic numerals.
Case 9c—
Message
| 1156254676 | 2542294432 | 1949294015 | 1423217211 | 2979703115 |
| 4924213511 | 7424147875 | 7646252444 | 5143254845 | 3179742533 |
| 4055461512 | 7573227945 | 1627481511 | 7042351944 | 1378252149 |
| 2514764553 | 1548342126 | 7215254075 | 1611257845 | 4642217415 |
| 4952197929 | 7015242143 | 2925444933 | 1970187531 | 4079254829 |
| 4551491411 | 7321171554 |
An examination of this message shows it to consist of forty-four different two-figure groups running from 11 to 79. Let us prepare a frequency table of these groups.
| Group | Frequency |
| 11 | 111111 |
| 12 | 1 |
| 13 | 1 |
| 14 | 1111 |
| 15 | 111111111 |
| 16 | 11 |
| 17 | 1 |
| 18 | 1 |
| 19 | 1111 |
| 20 | |
| 21 | 1111111 |
| 22 | 1 |
| 23 | 1 |
| 24 | 1111 |
| 25 | 11111111111 |
| 26 | 1 |
| 27 | 1 |
| 28 | |
| 29 | 111111 |
| 30 | |
| 31 | 111 |
| 32 | 1 |
| 33 | 11 |
| 34 | 1 |
| 35 | 11 |
| 36 | |
| 37 | |
| 38 | |
| 39 | |
| 40 | 1111 |
| 41 | |
| 42 | 111 |
| 43 | 11 |
| 44 | 1111 |
| 45 | 11111 |
| 46 | 1111 |
| 47 | |
| 48 | 1111 |
| 49 | 111111 |
| 50 | |
| 51 | 11 |
| 52 | 1 |
| 53 | 1 |
| 54 | 1 |
| 55 | 1 |
| 56 | 1 |
| 57 | |
| 58 | |
| 59 | |
| 70 | 1111 |
| 71 | |
| 72 | 11 |
| 73 | 11 |
| 74 | 111 |
| 75 | 1111 |
| 76 | 111 |
| 77 | |
| 78 | 111 |
| 79 | 11111 |
We at once note the resemblance between the frequency tables for the groups 11 to 19 and 21 to 29; for the groups 30 to 36 and 50 to 56; and for the groups 40 to 49 and 70 to 79. Also the groups 11 to 19 and 21 to 29 have a frequency fitting well with the normal frequency table of the letters A to I; the groups 41 to 49 and 71 to 79 have a frequency fitting well with the normal frequency table of the letters K to S; and the groups 31 to 36 and 51 to 56 have a frequency fitting well with the normal frequency table of the letters U to Z. We have J and T unaccounted for, but note what occurred in Case 9-b and that 40 and 70 would correspond well with T if they followed respectively 49 and 79. We may now make up a cipher table as follows:
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | |
| 1 or 2 | A | B | C | D | E | F | G | H | I | J |
| 4 or 7 | K | L | M | N | O | P | Q | R | S | T |
| 3 or 5 | U | V | W | X | Y | Z |
and this table will solve the cipher message.
In ciphers coming under case 9-b and 9-c, it is not uncommon to assign some of the unused numbers such as 85, 93, etc., to whole words in common use or to names of persons or places. In case such groups are found, the meaning must be guessed at from the context; but if many messages in the same cipher are available, the meaning of these groups will soon be obtained. The appearance of such odd groups of figures in a message does not interfere materially with the analysis, and it will be apparent at once on deciphering the message that they represent whole words instead of letters.