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Encryption

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12
Question 2

The Vigenère cipher encrypts plaintext using a sequence of different Caesar ciphers, based on the letters of a keyword and a Vigenère square.

Figure 1 shows a Vigenère square.

Complete the table to perform a Vigenère decryption of the ciphertext message hmbqeiknce using the keyword pizza.

Figure 1: Vigenère square

abcdefghijklmnopqrstuvwxyz
aabcdefghijklmnopqrstuvwxyz
bbcdefghijklmnopqrstuvwxyza
ccdefghijklmnopqrstuvwxyzab
ddefghijklmnopqrstuvwxyzabc
eefghijklmnopqrstuvwxyzabcd
ffghijklmnopqrstuvwxyzabcde
gghijklmnopqrstuvwxyzabcdef
hhijklmnopqrstuvwxyzabcdefg
iijklmnopqrstuvwxyzabcdefgh
jjklmnopqrstuvwxyzabcdefghi
kklmnopqrstuvwxyzabcdefghij
llmnopqrstuvwxyzabcdefghijk
mmnopqrstuvwxyzabcdefghijkl
nnopqrstuvwxyzabcdefghijklm
oopqrstuvwxyzabcdefghijklmn
ppqrstuvwxyzabcdefghijklmno
qqrstuvwxyzabcdefghijklmnop
rrstuvwxyzabcdefghijklmnopq
sstuvwxyzabcdefghijklmnopqr
ttuvwxyzabcdefghijklmnopqrs
uuvwxyzabcdefghijklmnopqrst
vvwxyzabcdefghijklmnopqrstu
wwxyzabcdefghijklmnopqrstuv
xxyzabcdefghijklmnopqrstuvw
yyzabcdefghijklmnopqrstuvwx
zzabcdefghijklmnopqrstuvwxy

Decryption table

Encrypted letterhmbqeiknce
Keyword letter
Decrypted letter
[4]

Encryption Questions

  1. IGCSE
  2. /Computer Science
  3. /Encryption