strength = strength + " - " + z.feedback.warning;
};
}
- var bitsStr = entropy.binaryStr.length;
+ var bitsStr = getNumberOfEntropyBits(entropy);
var wordCount = Math.floor(entropy.binaryStr.length / 32) * 3;
DOM.entropyFiltered.html(entropy.cleanHtml);
DOM.entropyType.text(entropy.base.str);
DOM.entropyBitsPerEvent.text(Math.log2(entropy.base.asInt).toFixed(2));
}
+ function getNumberOfEntropyBits(entropy) {
+ var bitsStr = entropy.binaryStr.length.toString();
+ // If using cards, assume they are not reused, thus additional entropy
+ // decreases as more cards are used. This means 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 (entropy.base.asInt == 52) {
+ var totalCombos = factorial(52);
+ var remainingCards = 52 - entropy.base.parts.length;
+ var remainingCombos = factorial(remainingCards);
+ var currentCombos = totalCombos.divide(remainingCombos);
+ bitsStr = currentCombos.toString(2).length.toString();
+ }
+ return bitsStr
+ }
+
+ // Depends on BigInteger
+ function factorial(n) {
+ if (n == 0) {
+ return 1;
+ }
+ f = BigInteger.ONE;
+ for (var i=1; i<=n; i++) {
+ f = f.multiply(new BigInteger(i));
+ }
+ return f;
+ }
+
var networks = [
{
name: "Bitcoin",
[ "222F", "16" ],
[ "FFFF", "16" ],
[ "0000101017", "33" ], // 10 events at 3.32 bits per event
+ [ "ac2c3c4c5c6c7c8c9ctcjcqckcad2d3d4d5d6d7d8d9dtdjdqdkdah2h3h4h5h6h7h8h9hthjhqhkhas2s3s4s5s6s7s8s9stsjsqsks", "226" ], // cards are not replaced, so a full deck is not 52^52 entropy which is 296 bits, it's 52!, which is 226 bits
]
// use entropy
page.evaluate(function(e) {