+/*
+ * Detects entropy from a string.
+ *
+ * Formats include:
+ * binary [0-1]
+ * base 6 [0-5]
+ * dice 6 [1-6]
+ * decimal [0-9]
+ * hexadecimal [0-9A-F]
+ *
+ * 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
+ * entropy.
+ */
+
window.Entropy = new (function() {
+ // matchers returns an array of the matched events for each type of entropy.
+ // eg
+ // matchers.binary("010") returns ["0", "1", "0"]
+ // matchers.binary("a10") returns ["1", "0"]
+ // matchers.hex("a10") returns ["a", "1", "0"]
var matchers = {
- binary: /[0-1]/gi,
- base6: /[0-5]/gi,
- dice: /[1-6]/gi, // ie dice numbers
- base10: /[0-9]/gi,
- hex: /[0-9A-F]/gi,
+ binary: function(str) {
+ return str.match(/[0-1]/gi) || [];
+ },
+ base6: function(str) {
+ return str.match(/[0-5]/gi) || [];
+ },
+ dice: function(str) {
+ return str.match(/[1-6]/gi) || []; // ie dice numbers
+ },
+ base10: function(str) {
+ return str.match(/[0-9]/gi) || [];
+ },
+ 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) {
}
rawEntropyStr = newRawEntropyStr;
base.str = "base 6 (dice)";
+ base.parts = matchers.base6(rawEntropyStr);
base.matcher = matchers.base6;
}
- var entropyParts = rawEntropyStr.match(base.matcher) || [];
- var entropyStr = entropyParts.join("");
// Detect empty entropy
- if (entropyStr.length == 0) {
+ if (base.parts.length == 0) {
return {
binaryStr: "",
- hexStr: "",
cleanStr: "",
base: base,
};
}
// Pull leading zeros off
- var leadingZeros = "";
- while (entropyStr[0] == "0") {
- leadingZeros += "0";
- entropyStr = entropyStr.substring(1);
+ var leadingZeros = [];
+ while (base.ints[0] == "0") {
+ leadingZeros.push("0");
+ base.ints.shift();
}
// Convert leading zeros to binary equivalent
- var numBinLeadingZeros = Math.ceil(Math.log2(base.asInt) * leadingZeros.length);
+ var numBinLeadingZeros = Math.floor(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 (entropyStr == "") {
+ if (base.ints.length == 0) {
return {
binaryStr: binLeadingZeros,
- hexStr: hexLeadingZeros || "0",
cleanStr: leadingZeros,
base: base,
}
}
- // 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(entropyStr[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";
- }
+ // 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 unusual bases, eg base 6 has 2.6 bits, so is
+ // slightly biased toward having leading zeros, but it's still better
+ // than ignoring it completely.
+ // TODO: revise this, it seems very fishy. For example, in base 10, there are
+ // 8 opportunities to start with 0 but only 2 to start with 1
+ var firstInt = base.ints[0];
+ var firstIntBits = Math.floor(Math.log2(firstInt))+1;
+ var maxFirstIntBits = Math.floor(Math.log2(base.asInt-1))+1;
+ var missingFirstIntBits = maxFirstIntBits - firstIntBits;
+ var firstIntLeadingZeros = "";
+ for (var i=0; i<missingFirstIntBits; i++) {
+ binLeadingZeros += "0";
+ }
+ // 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 entropy to different foramts
- var entropyInt = BigInteger.parse(entropyStr, base.asInt);
+ // Convert entropy to different formats
var entropyBin = binLeadingZeros + entropyInt.toString(2);
- var entropyHex = hexLeadingZeros + entropyInt.toString(16);
- var entropyClean = leadingZeros + entropyStr;
+ var entropyClean = base.parts.join("");
var e = {
binaryStr: entropyBin,
- hexStr: entropyHex,
cleanStr: entropyClean,
base: base,
}
function getBase(str) {
// Need to get the lowest base for the supplied entropy.
// This prevents interpreting, say, dice rolls as hexadecimal.
- var binaryMatches = str.match(matchers.binary) || [];
- var base6Matches = str.match(matchers.base6) || [];
- var diceMatches = str.match(matchers.dice) || [];
- var base10Matches = str.match(matchers.base10) || [];
- var hexMatches = str.match(matchers.hex) || [];
+ 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",
}
}
- if (diceMatches.length == hexMatches.length) {
+ 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 && hexMatches.length > 0) {
+ var ints = diceMatches.map(function(i) { return parseInt(i) });
return {
+ ints: ints,
+ parts: diceMatches,
matcher: matchers.dice,
asInt: 6,
str: "dice",
}
}
- if (base6Matches.length == hexMatches.length) {
+ var base6Matches = matchers.base6(str);
+ 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,
str: "base 6",
}
}
- if (base10Matches.length == hexMatches.length) {
+ var base10Matches = matchers.base10(str);
+ 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,
str: "hexadecimal",
// 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);
};
})();
projects / perso / Immae / Projets / Cryptomonnaies / BIP39.git / blobdiff