From: Stephan Richter <github@keawe.de>
Date: Fri, 13 Oct 2017 13:32:43 +0000 (+0200)
Subject: secret.html
X-Git-Url: https://fpunktk.de/gitweb/?p=shamirs_secret_web_implementation.git;a=commitdiff_plain;h=725292dcaa215cbd02279f665ed109a26a223d93

secret.html
---

diff --git a/src/secret.html b/src/secret.html
index 324cf45..39bb322 100644
--- a/src/secret.html
+++ b/src/secret.html
@@ -62,19 +62,13 @@ function rand256(){
 
 /* Split number into the shares */
 function split(number, number_of_shares, needed) {
-    var coef = [number]
+    var coef = [number]; // first coefficient always equals the number itself.
     var shares = [];
-
-    for(var coef_index = 1; coef_index < needed; coef_index++){
-    	coef[coef_index] = rand256();
-    }
     
+    for(var coef_index = 1; coef_index < needed; coef_index++) coef[coef_index] = rand256();    
     for(var share_number = 1; share_number <= number_of_shares; share_number++) {
     	var sum = 0;
-    	for (var coef_index =0; coef_index<needed; coef_index++){
-    		sum += coef[coef_index]*Math.pow(share_number,coef_index);
-    	}
-    	
+    	for (var coef_index =0; coef_index<needed; coef_index++) sum += coef[coef_index]*Math.pow(share_number,coef_index);
     	shares[share_number-1] = sum % prime; 
     }
     return shares;
@@ -82,7 +76,10 @@ function split(number, number_of_shares, needed) {
 
 function collect(){
 	var divs=document.getElementsByClassName('share');
-	var shares=[],lastValue;
+	var shares=[];
+	var string;
+	
+	// gather values from the input fields
 	for (var div_index=0; div_index<divs.length; div_index++){
 		var div=divs[div_index];
 		var inputs = div.getElementsByTagName('input');
@@ -100,6 +97,8 @@ function collect(){
 			}
 		}
 	}	
+	
+	// the create new input fields on demand
 	if (string!=''){
 		var clone=div.cloneNode(true);
 		var inputs=clone.getElementsByTagName('input');
@@ -140,37 +139,45 @@ function join(shares) {
     return sum;
 }
 
-function decode(){
-	var shares_list=collect(); // fetch shares
-	var codeCount=null;
+/* get the number of codes from the list of shares */
+function numberOfCodesIn(shares_list){
+	var result=null;
 	for (var i=0; i<shares_list.length; i++) {
-		if (codeCount == null){		
-			codeCount = shares_list[i].parts.length;
+		if (result == null){		
+			result = shares_list[i].parts.length;
 		} else {
-			codeCount=Math.min(shares_list[i].parts.length,codeCount);
+			result=Math.min(shares_list[i].parts.length,result);
 		}		
 	}
+	return result;
+}
+
+/* fetches values from the input fields, decomposes each input string into several shares and reconstructs the original code/char for each position */
+function decode(){
+	var shares_list=collect(); // fetch shares
+	var ascii=getElement('ascii');
+	var result=getElement('result');	
 	
-	var ascii=document.getElementById('ascii');
 	ascii.innerHTML='ascii: ';
 	result.innerHTML='Passphrase: ';
 	
-	
+	var codeCount = numberOfCodesIn(shares_list);
 	for (var codeIndex = 0; codeIndex<codeCount; codeIndex++){
 		shares_for_code = [];
-		for (var share_index=0; share_index<shares_list.length; share_index++){
-			var share_number = shares_list[share_index].share_number;
-			var share = shares_list[share_index].parts[codeIndex];
-			shares_for_code[share_index] = { share_number, share };
-		}
+		
+		shares_list.forEach(function(share_set){
+			var share_number = share_set.share_number;
+			var share = share_set.parts[codeIndex];
+			shares_for_code.push({ share_number, share });
+		});
 		
 		var code = join(shares_for_code);
 		ascii.innerHTML += code+' ';
 		result.innerHTML+= String.fromCharCode(code);
-		
 	}
 }
 
+/* decomposes the given secrets into single characters. Then, the ascii code of each caracter is treated as secre and split into keys */
 function secret2numbers(string){
 	var string_pos,share_number,coef,char_code,x,sum;
 	var number_of_shares = valueOfField('shares');