Entropy library has extra comments for clarity

This commit is contained in:
Ian Coleman
2016-11-17 14:31:57 +11:00
parent 6422c1cd57
commit 0fdcf2eb53

View File

@@ -7,6 +7,7 @@
* dice 6 [1-6]
* decimal [0-9]
* hexadecimal [0-9A-F]
* card [A2-9TJQK][CDHS]
*
* Automatically uses lowest entropy to avoid issues such as interpretting 0101
* as hexadecimal which would be 16 bits when really it's only 4 bits of binary
@@ -119,11 +120,11 @@ window.Entropy = new (function() {
}
// Assume cards are NOT replaced.
// Additional entropy decreases as more cards are used. This means
// entropy is measured using n!, not base^n.
// total possible entropy is measured using n!, not base^n.
// eg the second last card can be only one of two, not one of fifty two
// so the added entropy for that card is only one bit at most
if (base.asInt == 52) {
// Get the maximum value without replacement
// Get the maximum value WITHOUT replacement
var totalDecks = Math.ceil(base.parts.length / 52);
var totalCards = totalDecks * 52;
var totalCombos = factorial(52).pow(totalDecks);
@@ -140,7 +141,7 @@ window.Entropy = new (function() {
if (numberOfBits < 32) {
maxWithoutReplace = BigInteger(Math.round(Math.pow(2, numberOfBits)));
}
// Get the maximum value with replacement
// Get the maximum value WITH replacement
var maxWithReplace = BigInteger.pow(52, base.parts.length);
// Calculate the new value by scaling the original value down
var withoutReplace = entropyInt.multiply(maxWithoutReplace).divide(maxWithReplace);
@@ -166,6 +167,7 @@ window.Entropy = new (function() {
entropyHtml = entropyHtml.replace(/H/g, "<span class='card-suit heart'>\u2665</span>");
entropyHtml = entropyHtml.replace(/S/g, "<span class='card-suit spade'>\u2660</span>");
}
// Return the result
var e = {
binaryStr: entropyBin,
cleanStr: entropyClean,