A transposition does not substitute one symbol for another, instead it changes the location of the symbol. A symbol in 1st position of plaintext may appear in the 10th position. A symbol in the 6th position in plaintext may appear in 1st position of cipher.In other words, a transposition cipher reorders the symbols
There are two types of Transposition Cipher:
1] Keyless: It is keyless cipher which does not uses a key for encryption.Two methods are there for keyless; Method 1 and Method 2
In Method 1: text is written in table by col by col & transmitted row by row.
Eg. Plaintext= meet me at the park
In Method 2: text written in table by row by row & transmitted column by column.
| m | e | e | t |
| m | e | a | t |
| t | h | e | p |
| a | r | k | |
2] Keyed: (Plaintext divided into groups called blocks, use key to permute the character in each block)
Plaintext: "Enemy attacks tonight"
Group plaintext into group of 5 characters as key is of length 5
Enemy | attac | kston | ightz
Keyword/ Secret key
$\uparrow$ Encryption $\downarrow$ Decryption
1) 1st character of ciphertext is the 3rd letter of the plaintext block
2) 2nd character of the ciphertext is the 1st character of plaintext & so on…
Ciphertext=EEMYN TAACT TKONS HITZG