1. Multiplicative Cipher / Decimation Cipher encoder
Text : ABCD efghi
Multiplication Key : 3
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:A multiplicative cipher encrypts a message by multiplying each letter's numerical value (0-25) by a fixed key (which is coprime to 26) and the corresponding letter is substituted.
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
(2) | 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 |
| ((2) * 3) Mod 26 | 0 | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | 1 | 4 | 7 | 10 | 13 | 16 | 19 | 22 | 25 | 2 | 5 | 8 | 11 | 14 | 17 | 20 | 23 |
| Substitute | a | d | g | j | m | p | s | v | y | b | e | h | k | n | q | t | w | z | c | f | i | l | o | r | u | x |
Each letter is multiplied with this key and the corresponding letter is substituted
| Plaintext | A | B | C | D | | e | f | g | h | i |
| Ciphertext | A | D | G | J | | m | p | s | v | y |
| Plaintext | : ABCD efghi |
| Multiplication Key | : 3 |
| Ciphertext | : ADGJ mpsvy |
2. Multiplicative Cipher / Decimation Cipher encoder
Text : hello world
Multiplication Key : 3
Alphabet : abcdefghijklmnopqrstuvwxyzSolution:A multiplicative cipher encrypts a message by multiplying each letter's numerical value (0-25) by a fixed key (which is coprime to 26) and the corresponding letter is substituted.
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
(2) | 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 |
| ((2) * 3) Mod 26 | 0 | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | 1 | 4 | 7 | 10 | 13 | 16 | 19 | 22 | 25 | 2 | 5 | 8 | 11 | 14 | 17 | 20 | 23 |
| Substitute | a | d | g | j | m | p | s | v | y | b | e | h | k | n | q | t | w | z | c | f | i | l | o | r | u | x |
Each letter is multiplied with this key and the corresponding letter is substituted
| Plaintext | h | e | l | l | o | | w | o | r | l | d |
| Ciphertext | v | m | h | h | q | | o | q | z | h | j |
| Plaintext | : hello world |
| Multiplication Key | : 3 |
| Ciphertext | : vmhhq oqzhj |
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