diff --git a/Ciphers/keyFinder.js b/Ciphers/keyFinder.js
index 8dda33c3e..cb4160c45 100644
--- a/Ciphers/keyFinder.js
+++ b/Ciphers/keyFinder.js
@@ -3,23 +3,24 @@ Find and retrieve the encryption key automatically
 Note: This is a draft version, please help to modify, Thanks!
 ******************************************************/
 function keyFinder(str){ // str is used to get the input of encrypted string
-	var key = 0; // return zero means the key can not be found
-	var wordbank =["is","Is","am","Am","are","Are","have","Have","has","Has","may","May","be","Be"];
+	const wordbank =["is","Is","am","Am","are","Are","have","Have","has","Has","may","May","be","Be"];
+	let key = 0; // return zero means the key can not be found
  	//var shiftNum = 0; //count the number of key shifted
-	var inStr = str.toString(); //convert the input to String
-	var outStr = ""; // store the output value
-	var wordInOutStr = ""; // temporary store the word inside the outStr, it is used for comparison
+	let inStr = str.toString(); //convert the input to String
+	let outStr = ""; // store the output value
+	let wordInOutStr = ""; // temporary store the word inside the outStr, it is used for comparison
  	//document.getElementById("debug").innerHTML = shiftNum; // debug: display the shifted number(s) 
- 	for (var i=0; i<(52); i++){ //try the number of key shifted, the sum of character from a-z and A-Z is 26*2=52
+ 	for (let i=0; i<(52); i++){ //try the number of key shifted, the sum of character from a-z and A-Z is 26*2=52
 		outStr = caesarCipherEncodeAndDecodeEngine(inStr,i); // use the encrytpion engine to decrypt the input string, shiftNum=i
-		for ( var i=0; i<wordbank.length; i++){
+		for ( let i=0; i<wordbank.length; i++){
 			// use a loop to find the next digit of wordbank element and compare with outStr's digit
-			for ( var j=0; j < wordbank[i].length; j++){
+			for ( let j=0; j < wordbank[i].length; j++){
 				wordInOutStr += outStr[i+j];
 			}
 			// this part need to be optimize with the calculation of the number of occurance of word's probabilities
+			// linked list will be used in the next stage of development to calculate the number of occurace of the key
 			if (wordbank[i] == wordInOutStr){
-        			key=i;
+        			return key=i;
 			}
 		}
 	}