Update keyFinder.js

Ciphers/keyFinder.js

@@ -3,25 +3,155 @@ 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"];
- 	//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
- 	//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
-		outStr = caesarCipherEncodeAndDecodeEngine(inStr,i); // use the encrytpion engine to decrypt the input string, shiftNum=i
-		for ( var 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++){
-				wordInOutStr += outStr[i+j];
-			}
-			// this part need to be optimize with the calculation of the number of occurance of word's probabilities
-			if (wordbank[i] == wordInOutStr){
-        			key=i;
+	const wordbank =[" the ","The "," of "," is ","Is "," am ","Am "," are ","Are "," have ","Have "," has ","Has "," may ","May "," be ","Be "];
+	//let wordbankelementCounter = 0;
+	//let key = 0; // return zero means the key can not be found
+	let inStr = str.toString(); //convert the input to String
+	let outStr = ""; // store the output value
+	let outStrElement = ""; // temporary store the word inside the outStr, it is used for comparison
+ 	for (let k=0; k<26; k++){ //try the number of key shifted, the sum of character from a-z or A-Z is 26
+		outStr = caesarCipherEncodeAndDecodeEngine(inStr,k); // use the encrytpion engine to decrypt the input string
+
+		//loop through the whole input string
+		for ( let s=0; s < outStr.length; s++){
+
+			for ( let i=0; i < wordbank.length; i++){
+
+				// initialize the outStrElement which is a temp output string for comparison, 
+				// use a loop to find the next digit of wordbank element and compare with outStr's digit
+				for ( let w=0; w < wordbank[i].length; w++){
+					outStrElement += outStr[ s + w ];
+				}
+
+				//console.log( k + outStrElement + wordbank[i] );//debug
+
+				// 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] == outStrElement){
+        				return k; // return the key number if founded
+				}
+
+				outStrElement = ""; //reset the temp word
+
+			} // end for ( let i=0; i < wordbank.length; i++)
+
+		}
+
+	}
+	return 0; // return 0 if found nothing
+}
+
+/* this sub-function is used to assist the keyfinder to find the key */
+function caesarCipherEncodeAndDecodeEngine(inStr, numShifted)
+{
+	let shiftNum = numShifted; 
+	let charCode = 0;
+	let outStr = "";
+	let shftedcharCode = 0;
+	let result = 0;
+
+	for (let i=0; i<inStr.length; i++){
+
+		charCode = inStr[i].charCodeAt();
+		shftedcharCode = charCode + shiftNum;
+		result = charCode;
+
+		if ( (charCode>=48 && charCode<=57))
+		{
+			if ( shftedcharCode < 48 ){
+
+		  		let diff = Math.abs(48-1-shftedcharCode)%10;
+
+				while( diff >= 10){
+		  			diff = diff%10;
+				}
+				document.getElementById("diffID").innerHTML = diff;
+
+				shftedcharCode = 57-diff;
+
+				result = shftedcharCode;
+			}
+
+		  	else if ( shftedcharCode>=48 && shftedcharCode<=57 ){
+				result = shftedcharCode;
+			}
+
+			else if ( shftedcharCode > 57 ){
+
+		  		let diff = Math.abs(57+1-shftedcharCode)%10;
+
+				while( diff >= 10){
+		  			diff = diff%10;
+				}
+				document.getElementById("diffID").innerHTML = diff;
+
+				shftedcharCode = 48+diff;
+
+				result = shftedcharCode;
+			}
+
+
+		}
+
+		else if ( (charCode>=65 && charCode<=90) )
+		{
+
+		  	if (shftedcharCode <=64 ){
+
+		  		let diff = Math.abs(65-1-shftedcharCode)%26;
+
+				while( (diff%26) >= 26){
+		  			diff = diff%26;
+				}
+				shftedcharCode = 90-diff;
+				result = shftedcharCode;
+			}
+
+		  	else if ( shftedcharCode>=65 && shftedcharCode<=90 ){
+				result = shftedcharCode;
+			}
+
+			else if (shftedcharCode>90 ){
+				let diff = Math.abs(shftedcharCode-1-90)%26;
+
+				while( (diff%26) >= 26){
+		  			diff = diff%26;
+				}
+				shftedcharCode = 65+diff;
+				result = shftedcharCode;
+			}
+
+		}
+
+		else if ( (charCode>=97 && charCode<=122))
+		{
+		  	if ( shftedcharCode<=96 ){
+
+		  		let diff = Math.abs(97-1-shftedcharCode)%26;
+
+				while( (diff%26) >= 26){
+		  			diff = diff%26;
+				}
+				shftedcharCode = 122-diff;
+				result = shftedcharCode;
+			}
+
+		  	else if ( shftedcharCode>=97 && shftedcharCode<=122 ){
+				result = shftedcharCode;
+			}
+
+			else if (shftedcharCode>122 ){
+				let diff = Math.abs(shftedcharCode-1-122)%26;
+
+				while( (diff%26) >= 26){
+		  			diff = diff%26;
+				}
+				shftedcharCode = 97+diff;
+				result = shftedcharCode;
 			}
+
 		}
+		outStr = outStr + String.fromCharCode(parseInt(result));
 	}
-	return key;
+	return outStr;
 }