Update README.md

Author: harshildarji

README.md

@@ -82,13 +82,17 @@ Add comments here
 ## Ciphers
 
 ### Caesar
-![alt text][caesar]
+![alt text][caesar]<br>
 In cryptography, a **Caesar cipher**, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques.<br>
 It is **a type of substitution cipher** in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. <br>
 The method is named after **Julius Caesar**, who used it in his private correspondence.<br>
 The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the Vigenère cipher, and still has modern application in the ROT13 system. As with all single-alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no communication security.
 ###### Source: [Wikipedia](https://en.wikipedia.org/wiki/Caesar_cipher)
 
+### Transposition
+In cryptography, a **transposition cipher** is a method of encryption by which the positions held by units of plaintext (which are commonly characters or groups of characters) are shifted according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed (the plaintext is reordered).<br> 
+Mathematically a bijective function is used on the characters' positions to encrypt and an inverse function to decrypt.
+###### Source: [Wikipedia](https://en.wikipedia.org/wiki/Transposition_cipher)
 [bubble-toptal]: https://www.toptal.com/developers/sorting-algorithms/bubble-sort
 [bubble-wiki]: https://en.wikipedia.org/wiki/Bubble_sort
 [bubble-image]: https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Bubblesort-edited-color.svg/220px-Bubblesort-edited-color.svg.png "Bubble Sort"