1. Running Key Cipher encoder
Text : ABCD efghi
Key : bcdefghijklm
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:The Running key cipher is a polyalphabetic substitution cipher that encrypts a message using a long non-repeating keyword
Alphabet = abcdefghijklmnopqrstuvwxyz
| Letter | 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 |
| Number | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 |
Each letter is shifted down based on the key letter
| Plaintext | A | B | C | D | | e | f | g | h | i |
Text Value
(2) | 0 | 1 | 2 | 3 | | 4 | 5 | 6 | 7 | 8 |
| Key | b | c | d | e | | f | g | h | i | j |
Key Value
(4) | 1 | 2 | 3 | 4 | | 5 | 6 | 7 | 8 | 9 |
Addition
(2) + (4) Mod 26 | 1 | 3 | 5 | 7 | | 9 | 11 | 13 | 15 | 17 |
| Ciphertext | B | D | F | H | | j | l | n | p | r |
| Plaintext | : ABCD efghi |
| Key | : bcdefghijklm |
| Ciphertext | : BDFH jlnpr |
2. Running Key Cipher encoder
Text : hello world
Key : bcdefghijklm
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:The Running key cipher is a polyalphabetic substitution cipher that encrypts a message using a long non-repeating keyword
Alphabet = abcdefghijklmnopqrstuvwxyz
| Letter | 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 |
| Number | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 |
Each letter is shifted down based on the key letter
| Plaintext | h | e | l | l | o | | w | o | r | l | d |
Text Value
(2) | 7 | 4 | 11 | 11 | 14 | | 22 | 14 | 17 | 11 | 3 |
| Key | b | c | d | e | f | | g | h | i | j | k |
Key Value
(4) | 1 | 2 | 3 | 4 | 5 | | 6 | 7 | 8 | 9 | 10 |
Addition
(2) + (4) Mod 26 | 8 | 6 | 14 | 15 | 19 | | 28=2 | 21 | 25 | 20 | 13 |
| Ciphertext | i | g | o | p | t | | c | v | z | u | n |
| Plaintext | : hello world |
| Key | : bcdefghijklm |
| Ciphertext | : igopt cvzun |
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