1. Bifid Cipher encoder
Text : ABCD efghi
Period / Length : 5
Alphabet25 : abcdefghiklmnopqrstuvwxyz
Coordinates Read Order : Row then ColumnSolution:The Bifid cipher is a 5x5 grid-based Polybius square cipher, that converts each letter into pair of coordinates (row, column), then rearrange them and convert them back to letters to get ciphertext
Alphabet = abcdefghiklmnopqrstuvwxyz
| 1 | 2 | 3 | 4 | 5 |
| 1 | a | b | c | d | e |
| 2 | f | g | h | i | k |
| 3 | l | m | n | o | p |
| 4 | q | r | s | t | u |
| 5 | v | w | x | y | z |
The text is converted to its coordinates (row, column), then written vertically, in group of 5 columns| Plaintext | a | b | c | d | e | f | g | h | i |
| Text coordinates | 11 | 12 | 13 | 14 | 15 | 21 | 22 | 23 | 24 |
| Row | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 |
| Col | 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 |
Read each group in rows11111,12345 | 2222,1234
Now divided up into pairs again and this pairs turned back to letters| Combined coordinates | 11 | 11 | 11 | 23 | 45 | 22 | 22 | 12 | 34 |
| Ciphertext | a | a | a | h | u | g | g | b | o |
| Plaintext | : abcdefghi |
| Period | : 5 |
| Ciphertext | : aaahuggbo |
2. Bifid Cipher encoder
Text : hello world
Period / Length : 5
Alphabet25 : abcdefghiklmnopqrstuvwxyz
Coordinates Read Order : Row then ColumnSolution:The Bifid cipher is a 5x5 grid-based Polybius square cipher, that converts each letter into pair of coordinates (row, column), then rearrange them and convert them back to letters to get ciphertext
Alphabet = abcdefghiklmnopqrstuvwxyz
| 1 | 2 | 3 | 4 | 5 |
| 1 | a | b | c | d | e |
| 2 | f | g | h | i | k |
| 3 | l | m | n | o | p |
| 4 | q | r | s | t | u |
| 5 | v | w | x | y | z |
The text is converted to its coordinates (row, column), then written vertically, in group of 5 columns| Plaintext | h | e | l | l | o | w | o | r | l | d |
| Text coordinates | 23 | 15 | 31 | 31 | 34 | 52 | 34 | 42 | 31 | 14 |
| Row | 2 | 1 | 3 | 3 | 3 | 5 | 3 | 4 | 3 | 1 |
| Col | 3 | 5 | 1 | 1 | 4 | 2 | 4 | 2 | 1 | 4 |
Read each group in rows21333,35114 | 53431,24214
Now divided up into pairs again and this pairs turned back to letters| Combined coordinates | 21 | 33 | 33 | 51 | 14 | 53 | 43 | 12 | 42 | 14 |
| Ciphertext | f | n | n | v | d | x | s | b | r | d |
| Plaintext | : helloworld |
| Period | : 5 |
| Ciphertext | : fnnvdxsbrd |
This material is intended as a summary. Use your textbook for detail explanation.
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