A History of Cryptography - Introduction to Cryptography with Java Applets - page 13

Category Letters Most Common Letter

1 LSLLM FLYJL VLLLY KWV L

2 JTQJP AJYQJ TJKJJ REH J

3 VNMVK VVVLV RVEVV FFZ V

4 BEEMA ADNNH NCTHS TUN N

5 QZDAU TAFPK FMAUF TXP A

TABLE 1.11

Category Plaintext Letter Maps to Ciphertext Letter Shift value

18 = S

1 T L

2 = C

2 H J

17 = R

3 E V

0 = A

4 N N

12 = M

5 O A

TABLE 1.12

and based on this, we can recover the plaintext.

THEBE ARWEN TOVER THEMO UNTAI NYEAH THEDO GWENT ROUND THEHY
DRANT THECA TINTO THEHI GHEST SPOTH ECOUL DFIND

1.9 THE FULL VIGENERE CIPHER

The full Vigenere cipher is similar to the simple shift Vigenere in that it uses a keyword or
keyphrase. However, in the full Vigenere cipher, rather than using a series of shift values k 1 ,
k 2 , . . . , k n , each letter in the keyword refers to a general permutation e 1 , e 2 , . . . , e n of the
alphabet. Enciphering in this way is aided by the use of a table such as Table 1.13.