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.
| a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| a | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z |
| b | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a |
| c | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b |
| d | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c |
| e | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d |
| f | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e |
| g | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f |
| h | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g |
| i | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h |
| j | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i |
| k | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j |
| l | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k |
| m | m | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l |
| n | n | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m |
| o | o | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n |
| p | p | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o |
| q | q | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p |
| r | r | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q |
| s | s | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r |
| t | t | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s |
| u | u | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t |
| v | v | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u |
| w | w | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v |
| x | x | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w |
| y | y | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x |
| z | z | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y |
| Encrypted letter | h | m | b | q | e | i | k | n | c | e |
| Keyword letter | ||||||||||
| Decrypted letter |
16 exam-style questions on Edexcel IGCSE Computer Science Encryption. Each one has a worked solution and a mark scheme showing where the marks go.