X-Git-Url: https://git.immae.eu/?a=blobdiff_plain;f=src%2Fjs%2Findex.js;h=89f8d0dd006053d7f86233f74d313fce00127680;hb=02f05d3e467ba8ccf3fca2811eda847fc71e511f;hp=b03f2c8aee98a3c8d5606f898cc7b5803f7a12a5;hpb=d6fd8ebf8667cad13392aff185fa5da7a7e82cbe;p=perso%2FImmae%2FProjets%2FCryptomonnaies%2FBIP39.git diff --git a/src/js/index.js b/src/js/index.js index b03f2c8..89f8d0d 100644 --- a/src/js/index.js +++ b/src/js/index.js @@ -818,7 +818,7 @@ 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); @@ -830,6 +830,35 @@ 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",