X-Git-Url: https://git.immae.eu/?a=blobdiff_plain;f=src%2Fjs%2Fentropy.js;h=0b76dcfef0afbdfb8f8de5103bb090828718fa9f;hb=b54c12180e5f4eb633e587551715707ec0523943;hp=5b687d8f6e3d1091ba2796a9d14629d9952ecff4;hpb=6606c50fd3af59483a5524170d9d2c3ec213a60f;p=perso%2FImmae%2FProjets%2FCryptomonnaies%2FBIP39.git

diff --git a/src/js/entropy.js b/src/js/entropy.js
index 5b687d8..0b76dcf 100644
--- a/src/js/entropy.js
+++ b/src/js/entropy.js
@@ -36,88 +36,106 @@ window.Entropy = new (function() {
         hex: function(str) {
             return str.match(/[0-9A-F]/gi) || [];
         },
+        card: function(str) {
+            // Format is NumberSuit, eg
+            // AH ace of hearts
+            // 8C eight of clubs
+            // TD ten of diamonds
+            // JS jack of spades
+            // QH queen of hearts
+            // KC king of clubs
+            return str.match(/([A2-9TJQK][CDHS])/gi) || [];
+        }
+    }
+
+    // Convert array of cards from ["ac", "4d", "ks"]
+    // to numbers between 0 and 51 [0, 16, 51]
+    function convertCardsToInts(cards) {
+        var ints = [];
+        var values = "a23456789tjqk";
+        var suits = "cdhs";
+        for (var i=0; i<cards.length; i++) {
+            var card = cards[i].toLowerCase();
+            var value = card[0];
+            var suit = card[1];
+            var asInt = 13 * suits.indexOf(suit) + values.indexOf(value);
+            ints.push(asInt);
+        }
+        return ints;
     }
 
     this.fromString = function(rawEntropyStr) {
         // Find type of entropy being used (binary, hex, dice etc)
         var base = getBase(rawEntropyStr);
         // Convert dice to base6 entropy (ie 1-6 to 0-5)
+        // This is done by changing all 6s to 0s
         if (base.str == "dice") {
-            var newRawEntropyStr = "";
-            for (var i=0; i<rawEntropyStr.length; i++) {
-                var c = rawEntropyStr[i];
-                if ("123456".indexOf(c) > -1) {
-                    newRawEntropyStr += (parseInt(c) - 1).toString();
+            var newParts = [];
+            var newInts = [];
+            for (var i=0; i<base.parts.length; i++) {
+                var c = base.parts[i];
+                if ("12345".indexOf(c) > -1) {
+                    newParts[i] = base.parts[i];
+                    newInts[i] = base.ints[i];
                 }
                 else {
-                    newRawEntropyStr += c
+                    newParts[i] = "0";
+                    newInts[i] = 0;
                 }
             }
-            rawEntropyStr = newRawEntropyStr;
             base.str = "base 6 (dice)";
-            base.parts = matchers.base6(rawEntropyStr);
+            base.ints = newInts;
+            base.parts = newParts;
             base.matcher = matchers.base6;
         }
         // Detect empty entropy
         if (base.parts.length == 0) {
             return {
                 binaryStr: "",
-                hexStr: "",
                 cleanStr: "",
+                cleanHtml: "",
                 base: base,
             };
         }
-        // Pull leading zeros off
-        var leadingZeros = [];
-        while (base.parts[0] == "0") {
-            leadingZeros.push("0");
-            base.parts.shift();
+        // Convert base.ints to BigInteger.
+        // Due to using unusual bases, eg cards of base52, this is not as simple as
+        // using BigInteger.parse()
+        var entropyInt = BigInteger.ZERO;
+        for (var i=base.ints.length-1; i>=0; i--) {
+            var thisInt = BigInteger.parse(base.ints[i]);
+            var power = (base.ints.length - 1) - i;
+            var additionalEntropy = BigInteger.parse(base.asInt).pow(power).multiply(thisInt);
+            entropyInt = entropyInt.add(additionalEntropy);
         }
-        // Convert leading zeros to binary equivalent
-        var numBinLeadingZeros = Math.ceil(Math.log2(base.asInt) * leadingZeros.length);
-        var binLeadingZeros = "";
-        for (var i=0; i<numBinLeadingZeros; i++) {
-            binLeadingZeros += "0";
-        }
-        // Convert leading zeros to hex equivalent
-        var numHexLeadingZeros = Math.floor(numBinLeadingZeros / 4);
-        var hexLeadingZeros = "";
-        for (var i=0; i<numHexLeadingZeros; i++) {
-            hexLeadingZeros += "0";
-        }
-        // Handle entropy of zero
-        if (base.parts.length == 0) {
-            return {
-                binaryStr: binLeadingZeros,
-                hexStr: hexLeadingZeros || "0",
-                cleanStr: leadingZeros,
-                base: base,
-            }
+        // Convert entropy to binary
+        var entropyBin = entropyInt.toString(2);
+        // If the first integer is small, it must be padded with zeros.
+        // Otherwise the chance of the first bit being 1 is 100%, which is
+        // obviously incorrect.
+        // This is not perfect for non-2^n bases.
+        var expectedBits = Math.floor(base.parts.length * Math.log2(base.asInt));
+        while (entropyBin.length < expectedBits) {
+            entropyBin = "0" + entropyBin;
         }
-        // If using hex, should always be multiples of 4 bits, which can get
-        // out of sync if first number has leading 0 bits, eg 2 in hex is 0010
-        // which would show up as 10, thus missing 2 bits it should have.
-        if (base.asInt == 16) {
-            var firstDigit = parseInt(base.parts[0], 16);
-            if (firstDigit >= 4 && firstDigit < 8) {
-                binLeadingZeros += "0";
-            }
-            else if (firstDigit >= 2 && firstDigit < 4) {
-                binLeadingZeros += "00";
-            }
-            else if (firstDigit >= 1 && firstDigit < 2) {
-                binLeadingZeros += "000";
-            }
+        // Supply a 'filtered' entropy string for display purposes
+        var entropyClean = base.parts.join("");
+        var entropyHtml = base.parts.join("");
+        if (base.asInt == 52) {
+            entropyClean = base.parts.join(" ").toUpperCase();
+            entropyClean = entropyClean.replace(/C/g, "\u2663");
+            entropyClean = entropyClean.replace(/D/g, "\u2666");
+            entropyClean = entropyClean.replace(/H/g, "\u2665");
+            entropyClean = entropyClean.replace(/S/g, "\u2660");
+            entropyHtml = base.parts.join(" ").toUpperCase();
+            entropyHtml = entropyHtml.replace(/C/g, "<span class='card-suit club'>\u2663</span>");
+            entropyHtml = entropyHtml.replace(/D/g, "<span class='card-suit diamond'>\u2666</span>");
+            entropyHtml = entropyHtml.replace(/H/g, "<span class='card-suit heart'>\u2665</span>");
+            entropyHtml = entropyHtml.replace(/S/g, "<span class='card-suit spade'>\u2660</span>");
         }
-        // Convert entropy to different foramts
-        var entropyInt = BigInteger.parse(base.parts.join(""), base.asInt);
-        var entropyBin = binLeadingZeros + entropyInt.toString(2);
-        var entropyHex = hexLeadingZeros + entropyInt.toString(16);
-        var entropyClean = leadingZeros.join("") + base.parts.join("");
         var e = {
             binaryStr: entropyBin,
-            hexStr: entropyHex,
             cleanStr: entropyClean,
+            cleanHtml: entropyHtml,
             base: base,
         }
         return e;
@@ -129,17 +147,32 @@ window.Entropy = new (function() {
         var binaryMatches = matchers.binary(str);
         var hexMatches = matchers.hex(str);
         // Find the lowest base that can be used, whilst ignoring any irrelevant chars
-        if (binaryMatches.length == hexMatches.length) {
+        if (binaryMatches.length == hexMatches.length && hexMatches.length > 0) {
+            var ints = binaryMatches.map(function(i) { return parseInt(i, 2) });
             return {
+                ints: ints,
                 parts: binaryMatches,
                 matcher: matchers.binary,
                 asInt: 2,
                 str: "binary",
             }
         }
+        var cardMatches = matchers.card(str);
+        if (cardMatches.length >= hexMatches.length / 2) {
+            var ints = convertCardsToInts(cardMatches);
+            return {
+                ints: ints,
+                parts: cardMatches,
+                matcher: matchers.card,
+                asInt: 52,
+                str: "card",
+            }
+        }
         var diceMatches = matchers.dice(str);
-        if (diceMatches.length == hexMatches.length) {
+        if (diceMatches.length == hexMatches.length && hexMatches.length > 0) {
+            var ints = diceMatches.map(function(i) { return parseInt(i) });
             return {
+                ints: ints,
                 parts: diceMatches,
                 matcher: matchers.dice,
                 asInt: 6,
@@ -147,8 +180,10 @@ window.Entropy = new (function() {
             }
         }
         var base6Matches = matchers.base6(str);
-        if (base6Matches.length == hexMatches.length) {
+        if (base6Matches.length == hexMatches.length && hexMatches.length > 0) {
+            var ints = base6Matches.map(function(i) { return parseInt(i) });
             return {
+                ints: ints,
                 parts: base6Matches,
                 matcher: matchers.base6,
                 asInt: 6,
@@ -156,15 +191,19 @@ window.Entropy = new (function() {
             }
         }
         var base10Matches = matchers.base10(str);
-        if (base10Matches.length == hexMatches.length) {
+        if (base10Matches.length == hexMatches.length && hexMatches.length > 0) {
+            var ints = base10Matches.map(function(i) { return parseInt(i) });
             return {
+                ints: ints,
                 parts: base10Matches,
                 matcher: matchers.base10,
                 asInt: 10,
                 str: "base 10",
             }
         }
+        var ints = hexMatches.map(function(i) { return parseInt(i, 16) });
         return {
+            ints: ints,
             parts: hexMatches,
             matcher: matchers.hex,
             asInt: 16,
@@ -175,7 +214,11 @@ window.Entropy = new (function() {
     // Polyfill for Math.log2
     // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log2#Polyfill
     Math.log2 = Math.log2 || function(x) {
-        return Math.log(x) * Math.LOG2E;
+        // The polyfill isn't good enough because of the poor accuracy of
+        // Math.LOG2E
+        // log2(8) gave 2.9999999999999996 which when floored causes issues.
+        // So instead use the BigInteger library to get it right.
+        return BigInteger.log(x) / BigInteger.log(2);
     };
 
 })();