forked from alecthomas/gometalinter
/
scoring.go
180 lines (153 loc) · 4.68 KB
/
scoring.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
package scoring
import (
"fmt"
"github.com/nbutton23/zxcvbn-go/entropy"
"github.com/nbutton23/zxcvbn-go/match"
"github.com/nbutton23/zxcvbn-go/utils/math"
"math"
"sort"
)
const (
START_UPPER string = `^[A-Z][^A-Z]+$`
END_UPPER string = `^[^A-Z]+[A-Z]$'`
ALL_UPPER string = `^[A-Z]+$`
//for a hash function like bcrypt/scrypt/PBKDF2, 10ms per guess is a safe lower bound.
//(usually a guess would take longer -- this assumes fast hardware and a small work factor.)
//adjust for your site accordingly if you use another hash function, possibly by
//several orders of magnitude!
SINGLE_GUESS float64 = 0.010
NUM_ATTACKERS float64 = 100 //Cores used to make guesses
SECONDS_PER_GUESS float64 = SINGLE_GUESS / NUM_ATTACKERS
)
type MinEntropyMatch struct {
Password string
Entropy float64
MatchSequence []match.Match
CrackTime float64
CrackTimeDisplay string
Score int
CalcTime float64
}
/*
Returns minimum entropy
Takes a list of overlapping matches, returns the non-overlapping sublist with
minimum entropy. O(nm) dp alg for length-n password with m candidate matches.
*/
func MinimumEntropyMatchSequence(password string, matches []match.Match) MinEntropyMatch {
bruteforceCardinality := float64(entropy.CalcBruteForceCardinality(password))
upToK := make([]float64, len(password))
backPointers := make([]match.Match, len(password))
for k := 0; k < len(password); k++ {
upToK[k] = get(upToK, k-1) + math.Log2(bruteforceCardinality)
for _, match := range matches {
if match.J != k {
continue
}
i, j := match.I, match.J
//see if best entropy up to i-1 + entropy of match is less that current min at j
upTo := get(upToK, i-1)
candidateEntropy := upTo + match.Entropy
if candidateEntropy < upToK[j] {
upToK[j] = candidateEntropy
match.Entropy = candidateEntropy
backPointers[j] = match
}
}
}
//walk backwards and decode the best sequence
var matchSequence []match.Match
passwordLen := len(password)
passwordLen--
for k := passwordLen; k >= 0; {
match := backPointers[k]
if match.Pattern != "" {
matchSequence = append(matchSequence, match)
k = match.I - 1
} else {
k--
}
}
sort.Sort(match.Matches(matchSequence))
makeBruteForceMatch := func(i, j int) match.Match {
return match.Match{Pattern: "bruteforce",
I: i,
J: j,
Token: password[i : j+1],
Entropy: math.Log2(math.Pow(bruteforceCardinality, float64(j-i)))}
}
k := 0
var matchSequenceCopy []match.Match
for _, match := range matchSequence {
i, j := match.I, match.J
if i-k > 0 {
matchSequenceCopy = append(matchSequenceCopy, makeBruteForceMatch(k, i-1))
}
k = j + 1
matchSequenceCopy = append(matchSequenceCopy, match)
}
if k < len(password) {
matchSequenceCopy = append(matchSequenceCopy, makeBruteForceMatch(k, len(password)-1))
}
var minEntropy float64
if len(password) == 0 {
minEntropy = float64(0)
} else {
minEntropy = upToK[len(password)-1]
}
crackTime := roundToXDigits(entropyToCrackTime(minEntropy), 3)
return MinEntropyMatch{Password: password,
Entropy: roundToXDigits(minEntropy, 3),
MatchSequence: matchSequenceCopy,
CrackTime: crackTime,
CrackTimeDisplay: displayTime(crackTime),
Score: crackTimeToScore(crackTime)}
}
func get(a []float64, i int) float64 {
if i < 0 || i >= len(a) {
return float64(0)
}
return a[i]
}
func entropyToCrackTime(entropy float64) float64 {
crackTime := (0.5 * math.Pow(float64(2), entropy)) * SECONDS_PER_GUESS
return crackTime
}
func roundToXDigits(number float64, digits int) float64 {
return zxcvbn_math.Round(number, .5, digits)
}
func displayTime(seconds float64) string {
formater := "%.1f %s"
minute := float64(60)
hour := minute * float64(60)
day := hour * float64(24)
month := day * float64(31)
year := month * float64(12)
century := year * float64(100)
if seconds < minute {
return "instant"
} else if seconds < hour {
return fmt.Sprintf(formater, (1 + math.Ceil(seconds/minute)), "minutes")
} else if seconds < day {
return fmt.Sprintf(formater, (1 + math.Ceil(seconds/hour)), "hours")
} else if seconds < month {
return fmt.Sprintf(formater, (1 + math.Ceil(seconds/day)), "days")
} else if seconds < year {
return fmt.Sprintf(formater, (1 + math.Ceil(seconds/month)), "months")
} else if seconds < century {
return fmt.Sprintf(formater, (1 + math.Ceil(seconds/century)), "years")
} else {
return "centuries"
}
}
func crackTimeToScore(seconds float64) int {
if seconds < math.Pow(10, 2) {
return 0
} else if seconds < math.Pow(10, 4) {
return 1
} else if seconds < math.Pow(10, 6) {
return 2
} else if seconds < math.Pow(10, 8) {
return 3
}
return 4
}