1. Gronsfeld Cipher encoder
Text : ABCD efghi
Digital Key : 123
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:The Gronsfeld cipher is a polyalphabetic substitution cipher that uses a repeating digit key instead of letters
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 |
Digital Key (repeated)
(3) | 1 | 2 | 3 | 1 | | 2 | 3 | 1 | 2 | 3 |
Addition
(2) + (3) Mod 26 | 1 | 3 | 5 | 4 | | 6 | 8 | 7 | 9 | 11 |
| Ciphertext | B | D | F | E | | g | i | h | j | l |
| Plaintext | : ABCD efghi |
| Digital Key | : 123 |
| Ciphertext | : BDFE gihjl |
2. Gronsfeld Cipher encoder
Text : hello world
Digital Key : 123
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:The Gronsfeld cipher is a polyalphabetic substitution cipher that uses a repeating digit key instead of letters
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 |
Digital Key (repeated)
(3) | 1 | 2 | 3 | 1 | 2 | | 3 | 1 | 2 | 3 | 1 |
Addition
(2) + (3) Mod 26 | 8 | 6 | 14 | 12 | 16 | | 25 | 15 | 19 | 14 | 4 |
| Ciphertext | i | g | o | m | q | | z | p | t | o | e |
| Plaintext | : hello world |
| Digital Key | : 123 |
| Ciphertext | : igomq zptoe |
This material is intended as a summary. Use your textbook for detail explanation.
Any bug, improvement, feedback then
