new: parsing BLE flags and company identifiers from advertisements

vendor/github.com/nbutton23/zxcvbn-go/entropy/entropyCalculator.go

@@ -0,0 +1,215 @@
+package entropy
+
+import (
+	"github.com/nbutton23/zxcvbn-go/adjacency"
+	"github.com/nbutton23/zxcvbn-go/match"
+	"github.com/nbutton23/zxcvbn-go/utils/math"
+	"math"
+	"regexp"
+	"unicode"
+)
+
+const (
+	START_UPPER string = `^[A-Z][^A-Z]+$`
+	END_UPPER   string = `^[^A-Z]+[A-Z]$'`
+	ALL_UPPER   string = `^[A-Z]+$`
+	NUM_YEARS          = float64(119) // years match against 1900 - 2019
+	NUM_MONTHS         = float64(12)
+	NUM_DAYS           = float64(31)
+)
+
+var (
+	KEYPAD_STARTING_POSITIONS = len(adjacency.AdjacencyGph["keypad"].Graph)
+	KEYPAD_AVG_DEGREE         = adjacency.AdjacencyGph["keypad"].CalculateAvgDegree()
+)
+
+func DictionaryEntropy(match match.Match, rank float64) float64 {
+	baseEntropy := math.Log2(rank)
+	upperCaseEntropy := extraUpperCaseEntropy(match)
+	//TODO: L33t
+	return baseEntropy + upperCaseEntropy
+}
+
+func extraUpperCaseEntropy(match match.Match) float64 {
+	word := match.Token
+
+	allLower := true
+
+	for _, char := range word {
+		if unicode.IsUpper(char) {
+			allLower = false
+			break
+		}
+	}
+	if allLower {
+		return float64(0)
+	}
+
+	//a capitalized word is the most common capitalization scheme,
+	//so it only doubles the search space (uncapitalized + capitalized): 1 extra bit of entropy.
+	//allcaps and end-capitalized are common enough too, underestimate as 1 extra bit to be safe.
+
+	for _, regex := range []string{START_UPPER, END_UPPER, ALL_UPPER} {
+		matcher := regexp.MustCompile(regex)
+
+		if matcher.MatchString(word) {
+			return float64(1)
+		}
+	}
+	//Otherwise calculate the number of ways to capitalize U+L uppercase+lowercase letters with U uppercase letters or
+	//less. Or, if there's more uppercase than lower (for e.g. PASSwORD), the number of ways to lowercase U+L letters
+	//with L lowercase letters or less.
+
+	countUpper, countLower := float64(0), float64(0)
+	for _, char := range word {
+		if unicode.IsUpper(char) {
+			countUpper++
+		} else if unicode.IsLower(char) {
+			countLower++
+		}
+	}
+	totalLenght := countLower + countUpper
+	var possibililities float64
+
+	for i := float64(0); i <= math.Min(countUpper, countLower); i++ {
+		possibililities += float64(zxcvbn_math.NChoseK(totalLenght, i))
+	}
+
+	if possibililities < 1 {
+		return float64(1)
+	}
+
+	return float64(math.Log2(possibililities))
+}
+
+func SpatialEntropy(match match.Match, turns int, shiftCount int) float64 {
+	var s, d float64
+	if match.DictionaryName == "qwerty" || match.DictionaryName == "dvorak" {
+		//todo: verify qwerty and dvorak have the same length and degree
+		s = float64(len(adjacency.BuildQwerty().Graph))
+		d = adjacency.BuildQwerty().CalculateAvgDegree()
+	} else {
+		s = float64(KEYPAD_STARTING_POSITIONS)
+		d = KEYPAD_AVG_DEGREE
+	}
+
+	possibilities := float64(0)
+
+	length := float64(len(match.Token))
+
+	//TODO: Should this be <= or just < ?
+	//Estimate the number of possible patterns w/ length L or less with t turns or less
+	for i := float64(2); i <= length+1; i++ {
+		possibleTurns := math.Min(float64(turns), i-1)
+		for j := float64(1); j <= possibleTurns+1; j++ {
+			x := zxcvbn_math.NChoseK(i-1, j-1) * s * math.Pow(d, j)
+			possibilities += x
+		}
+	}
+
+	entropy := math.Log2(possibilities)
+	//add extra entropu for shifted keys. ( % instead of 5 A instead of a)
+	//Math is similar to extra entropy for uppercase letters in dictionary matches.
+
+	if S := float64(shiftCount); S > float64(0) {
+		possibilities = float64(0)
+		U := length - S
+
+		for i := float64(0); i < math.Min(S, U)+1; i++ {
+			possibilities += zxcvbn_math.NChoseK(S+U, i)
+		}
+
+		entropy += math.Log2(possibilities)
+	}
+
+	return entropy
+}
+
+func RepeatEntropy(match match.Match) float64 {
+	cardinality := CalcBruteForceCardinality(match.Token)
+	entropy := math.Log2(cardinality * float64(len(match.Token)))
+
+	return entropy
+}
+
+//TODO: Validate against python
+func CalcBruteForceCardinality(password string) float64 {
+	lower, upper, digits, symbols := float64(0), float64(0), float64(0), float64(0)
+
+	for _, char := range password {
+		if unicode.IsLower(char) {
+			lower = float64(26)
+		} else if unicode.IsDigit(char) {
+			digits = float64(10)
+		} else if unicode.IsUpper(char) {
+			upper = float64(26)
+		} else {
+			symbols = float64(33)
+		}
+	}
+
+	cardinality := lower + upper + digits + symbols
+	return cardinality
+}
+
+func SequenceEntropy(match match.Match, dictionaryLength int, ascending bool) float64 {
+	firstChar := match.Token[0]
+	baseEntropy := float64(0)
+	if string(firstChar) == "a" || string(firstChar) == "1" {
+		baseEntropy = float64(0)
+	} else {
+		baseEntropy = math.Log2(float64(dictionaryLength))
+		//TODO: should this be just the first or any char?
+		if unicode.IsUpper(rune(firstChar)) {
+			baseEntropy++
+		}
+	}
+
+	if !ascending {
+		baseEntropy++
+	}
+	return baseEntropy + math.Log2(float64(len(match.Token)))
+}
+
+func ExtraLeetEntropy(match match.Match, password string) float64 {
+	var subsitutions float64
+	var unsub float64
+	subPassword := password[match.I:match.J]
+	for index, char := range subPassword {
+		if string(char) != string(match.Token[index]) {
+			subsitutions++
+		} else {
+			//TODO: Make this only true for 1337 chars that are not subs?
+			unsub++
+		}
+	}
+
+	var possibilities float64
+
+	for i := float64(0); i <= math.Min(subsitutions, unsub)+1; i++ {
+		possibilities += zxcvbn_math.NChoseK(subsitutions+unsub, i)
+	}
+
+	if possibilities <= 1 {
+		return float64(1)
+	}
+	return math.Log2(possibilities)
+}
+
+func YearEntropy(dateMatch match.DateMatch) float64 {
+	return math.Log2(NUM_YEARS)
+}
+
+func DateEntropy(dateMatch match.DateMatch) float64 {
+	var entropy float64
+	if dateMatch.Year < 100 {
+		entropy = math.Log2(NUM_DAYS * NUM_MONTHS * 100)
+	} else {
+		entropy = math.Log2(NUM_DAYS * NUM_MONTHS * NUM_YEARS)
+	}
+
+	if dateMatch.Separator != "" {
+		entropy += 2 //add two bits for separator selection [/,-,.,etc]
+	}
+	return entropy
+}