diff options
| author | Dmitry Vyukov <dvyukov@google.com> | 2020-07-04 11:12:55 +0200 |
|---|---|---|
| committer | Dmitry Vyukov <dvyukov@google.com> | 2020-07-04 15:05:30 +0200 |
| commit | c7d7f10bdff703e4a3c0414e8a33d4e45c91eb35 (patch) | |
| tree | 0dff0ee1f98dbfa3ad8776112053a450d176592b /vendor/github.com/nbutton23/zxcvbn-go/entropy | |
| parent | 9573094ce235bd9afe88f5da27a47dd6bcc1e13b (diff) | |
go.mod: vendor golangci-lint
Diffstat (limited to 'vendor/github.com/nbutton23/zxcvbn-go/entropy')
| -rw-r--r-- | vendor/github.com/nbutton23/zxcvbn-go/entropy/entropyCalculator.go | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/vendor/github.com/nbutton23/zxcvbn-go/entropy/entropyCalculator.go b/vendor/github.com/nbutton23/zxcvbn-go/entropy/entropyCalculator.go new file mode 100644 index 000000000..8f57ea0a4 --- /dev/null +++ b/vendor/github.com/nbutton23/zxcvbn-go/entropy/entropyCalculator.go @@ -0,0 +1,216 @@ +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 ( + numYears = float64(119) // years match against 1900 - 2019 + numMonths = float64(12) + numDays = float64(31) +) + +var ( + startUpperRx = regexp.MustCompile(`^[A-Z][^A-Z]+$`) + endUpperRx = regexp.MustCompile(`^[^A-Z]+[A-Z]$'`) + allUpperRx = regexp.MustCompile(`^[A-Z]+$`) + keyPadStartingPositions = len(adjacency.GraphMap["keypad"].Graph) + keyPadAvgDegree = adjacency.GraphMap["keypad"].CalculateAvgDegree() +) + +// DictionaryEntropy calculates the entropy of a dictionary match +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 _, matcher := range []*regexp.Regexp{startUpperRx, endUpperRx, allUpperRx} { + 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(zxcvbnmath.NChoseK(totalLenght, i)) + } + + if possibililities < 1 { + return float64(1) + } + + return float64(math.Log2(possibililities)) +} + +// SpatialEntropy calculates the entropy for spatial matches +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(keyPadStartingPositions) + d = keyPadAvgDegree + } + + 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 := zxcvbnmath.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 += zxcvbnmath.NChoseK(S+U, i) + } + + entropy += math.Log2(possibilities) + } + + return entropy +} + +// RepeatEntropy calculates the entropy for repeating entropy +func RepeatEntropy(match match.Match) float64 { + cardinality := CalcBruteForceCardinality(match.Token) + entropy := math.Log2(cardinality * float64(len(match.Token))) + + return entropy +} + +// CalcBruteForceCardinality calculates the brute force cardinality +//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 +} + +// SequenceEntropy calculates the entropy for sequences such as 4567 or cdef +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))) +} + +// ExtraLeetEntropy calulates the added entropy provied by l33t substitustions +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 += zxcvbnmath.NChoseK(subsitutions+unsub, i) + } + + if possibilities <= 1 { + return float64(1) + } + return math.Log2(possibilities) +} + +// DateEntropy calculates the entropy provided by a date +func DateEntropy(dateMatch match.DateMatch) float64 { + var entropy float64 + if dateMatch.Year < 100 { + entropy = math.Log2(numDays * numMonths * 100) + } else { + entropy = math.Log2(numDays * numMonths * numYears) + } + + if dateMatch.Separator != "" { + entropy += 2 //add two bits for separator selection [/,-,.,etc] + } + return entropy +} |
