new tasks

Task/Caesar_cipher/PHP/caesar_cipher.php

@@ -0,0 +1,19 @@
+<?php
+function caesarEncode( $message, $key ){
+    $plaintext = strtolower( $message );
+    $ciphertext = "";
+    $ascii_a = ord( 'a' );
+    $ascii_z = ord( 'z' );
+    while( strlen( $plaintext ) ){
+        $char = ord( $plaintext );
+        if( $char >= $ascii_a && $char <= $ascii_z ){
+            $char = ( ( $key + $char - $ascii_a ) % 26 ) + $ascii_a;
+        }
+        $plaintext = substr( $plaintext, 1 );
+        $ciphertext .= chr( $char );
+    }
+    return $ciphertext;
+}
+
+echo caesarEncode( "The quick brown fox Jumped over the lazy Dog", 12 ), "\n";
+?>