Transposition Cipher Techniques in Cryptography

In this article, we will learn about techniques used to encrypt the message earlier. This article will provide details about the Transposition Cipher Technique. Then we are going to explore various types of Transposition Cipher Technique.

The Transposition Cipher Technique is an encryption method used to encrypt a message or information. This encryption method is done by playing with the position of letters of the plain text. The positions of the characters present in the plaintext are rearranged or shifted to form the ciphertext. It makes use of some kind of permutation function to achieve the encryption purpose. It is very easy to use and so simple to implement.

There are three types of transposition cipher techniques

• Rail Fence Transposition Cipher
• Block (Single Columnar) Transposition Cipher
• Double Columnar Transposition Cipher

Rail Fence Transposition cipher technique is the simplest transposition cipher techniqueits. It is also termed as a zigzag cipher. It gets it’s name from the way through which it performs encryption of plain text.

The steps to get cipher text with the help of the Rail Fence Transposition cipher technique are follows:-

Technique of Rail Fence Transposition Cipher

Example: The plain text is “Hello Krishna”

Now, we will write this plain text in the diagonal form:

Now, following the second step we get our cipher text

Cipher Text = “rsnelkiha”

Block Transposition Cipher is another form of Transposition Cipher which was used to encrypt the message or information. In this technique, first, we write the message or plaintext in rows. After that, we read the message column by column. In this technique, we use a keyword to determine the no of rows.

• Step 1: First we write the message in the form of rows and columns, and read the message column by column.

• Step 2: Given a keyword, which we will use to fix the number of rows.

• Step 3: If any space is spared, it is filled with null or left blank or in by (_).

• Step 4: The message is read in the order as specified by the keyword.

For example: The plaintext is “KRISHNA RANJAN”

Now we will write the plaintext in the form of row and column.

Cipher Text = IAN_RNANS_J_KHRA

Double Columnar Transposition Cipher is another form of Transposition Cipher Technique. It is just similar to the columnar transposition technique. The main objective of using a Double Columnar Transposition Cipher is to encrypt the message twice. It makes use of the Single Columnar Transposition technique but uses two times. It can use the same or different secret keys. The output obtained from the first encryption will be the input to the second encryption.

• Step 1: First we write the message in the form of rows and columns, and read the message column by column.

• Step 2: Given a keyword, which we will use to fix the number of rows.

• Step 3: If any space is spared, it is filled with null or left blank or in by (_).

Now applying keyword 2

• Step 4: The message is read in the order in by the keyword.

Now applying step 3:

• Step 5: Then the output from the first encryption is input to the second.

• Step 6: Now the message is read in Technique in the order specified by the second keyword.

The Cipher Text is: “S_J_IAN_RNANKHRA”

In conclusion, Transposition Cipher Techniques are the techniques which are used for encryption of plaintext or messages. There are several types of Transposition Cipher Techniques which include Rail Fence Transposition Cipher, Block (Single Columnar) Transposition Cipher, and Double Columnar Transposition Cipher. Each technique has its way of encrypting the plaintext.

Name another term that is used for the Transposition technique

Another term used for Transposition technique is Translocation

Why do we use the Transposition Cipher technique?

Transposition Cipher Technique was used to pass on or transfer the message to the intended users in such a way that no third party can have access to the message.

Are block Transposition Cipher and Double Columnar Cipher Techniques the same?

The Block Transposition Cipher includes encryption of the message only once, but the Double Columnar Cipher Technique includes encryption of messages two times to provide more security.

Who invented the Transposition Cipher technique?

During the 4th century, the Greeks invented the Transposition Cipher techniques.

Write some applications of the in Cipher Technique

Some applications of Transposition Cipher Techniques are following:

• Communications in military
• security of message
• transfer of message to the intended user.