Made Changes to Readme.md

Author: Vignesh-dev07

Caesar cipher/README.md

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 # Caesar cipher 
 The Caesar Cipher technique is one of the earliest and simplest methods of encryption technique.
+It’s simply a type of substitution cipher, i.e., each letter of a given text is replaced by a letter with a fixed number of positions down the alphabet. For example with a shift of 1, A would be replaced by B, B would become C, and so on. The method is apparently named after Julius Caesar, who apparently used it to communicate with his officials. 
+
+Thus to cipher a given text we need an integer value, known as a shift which indicates the number of positions each letter of the text has been moved down.
+
+Examples :
+Text : ATTACKATONCE
+Shift: 4
+Cipher: EXXEGOEXSRGI
+
+Algorithm for Caesar Cipher: 
+Input: 
+
+1. A String of lower case letters, called Text.
+2. An Integer between 0-25 denoting the required shift.