private static double EstimateGuesses(ZxcvbnMatch match, string password)
{
if (match.Guesses.HasValue)
{
return(match.Guesses.Value);
}
int minGuesses = 1;
if (match.Token.Length < password.Length)
{
minGuesses = match.Token.Length == 1 ? minSubmatchGuessesSingleChar : minSubmatchGuessesMultiChar;
}
double guesses = match.Pattern switch
{
MatchPattern.Dictionary => DictionaryGuesses(match),
MatchPattern.Spatial => SpatialGuesses(match),
MatchPattern.Repeat => RepeatGuesses(match),
MatchPattern.Sequence => SequenceGuesses(match),
MatchPattern.Regex => RegexGuesses(match),
MatchPattern.Date => DateGuesses(match),
_ => BruteforceGuesses(match)
};
match.Guesses = Math.Max(guesses, minGuesses);
match.GuessesLog10 = Log10(match.Guesses.Value);
return(match.Guesses.Value);
}
private static double RegexGuesses(ZxcvbnMatch match)
{
return(match.RegexName switch
{
RegexName.RecentYear => Math.Max(Math.Abs(int.Parse(match.RegexMatch.Value) - referenceYear), minYearSpace),
RegexName.None => 0,
_ => Math.Pow((int)match.RegexName, match.Token.Length)
});
private static double SequenceGuesses(ZxcvbnMatch match)
{
char firstChar = match.Token[0];
double baseGuesses = obviousStartingPoints.Contains(match.Token[0]) ? 4 : (char.IsDigit(firstChar) ? 10 : 26);
if (!match.Ascending)
{
baseGuesses *= 2;
}
return(baseGuesses * match.Token.Length);
}
private static Feedback GetMatchFeedback(ZxcvbnMatch match, bool isSoleMatch)
{
return(match.Pattern switch
{
MatchPattern.Dictionary => GetDictionaryMatchFeedback(match, isSoleMatch),
MatchPattern.Spatial => new Feedback(match.Turns == 1 ? "Straight rows of keys are easy to guess" : "Short keyboard patterns are easy to guess", "Use a longer keyboard pattern with more turns"),
MatchPattern.Repeat => new Feedback(match.BaseToken.Length == 1 ? @"Repeats like ""aaa"" are easy to guess" : @"Repeats like ""abcabcabc"" are only slightly harder to guess than ""abc""", "Avoid repeated words and characters"),
MatchPattern.Sequence => new Feedback("Sequences like abc or 6543 are easy to guess", "Avoid sequences"),
MatchPattern.Regex => match.RegexName == RegexName.RecentYear ? new Feedback("Recent years are easy to guess", "Avoid recent years", "Avoid years that are associated with you") : Default,
MatchPattern.Date => new Feedback("Dates are often easy to guess", "Avoid dates and years that are associated with you"),
_ => Empty
});
private static double BruteforceGuesses(ZxcvbnMatch match)
{
double guesses = Math.Pow(bruteforceCardinality, match.Token.Length);
if (double.IsInfinity(guesses))
{
guesses = double.MaxValue;
}
double minGuesses = match.Token.Length == 1 ? minSubmatchGuessesSingleChar : minSubmatchGuessesMultiChar;
minGuesses += 1;
return(Math.Max(guesses, minGuesses));
}
internal static Feedback GetFeedback(double score, ZxcvbnMatch[] sequence)
{
if (sequence == null || sequence.Length == 0)
{
return(Default);
}
if (score > 2)
{
return(Empty);
}
ZxcvbnMatch longestMatch = sequence.OrderByDescending(m => m.Token.Length).First();
Feedback feedback = GetMatchFeedback(longestMatch, sequence.Length == 1);
feedback.Suggestions = feedback.Suggestions.Concat(new[] { "Add another word or two. Uncommon words are better." }).ToArray();
return(feedback);
}
public static ZxcvbnResult MostGuessableMatchSequence(string password, IEnumerable <ZxcvbnMatch> matches, bool excludeAdditive = false)
{
List <ZxcvbnMatch>[] matchesByJ = Enumerable.Range(0, password.Length).Select(i => new List <ZxcvbnMatch>()).ToArray();
for (int i = 0; i < password.Length; i++)
{
matchesByJ[i] = new List <ZxcvbnMatch>();
}
foreach (ZxcvbnMatch m in matches)
{
matchesByJ[m.J].Add(m);
}
foreach (List <ZxcvbnMatch> lst in matchesByJ)
{
lst.Sort((m1, m2) => m1.I - m2.I);
}
Dictionary <int, ZxcvbnMatch>[] optimalM = Enumerable.Range(0, password.Length).Select(i => new Dictionary <int, ZxcvbnMatch>()).ToArray();
Dictionary <int, double>[] optimalPi = Enumerable.Range(0, password.Length).Select(i => new Dictionary <int, double>()).ToArray();
Dictionary <int, double>[] optimalG = Enumerable.Range(0, password.Length).Select(i => new Dictionary <int, double>()).ToArray();
void Update(ZxcvbnMatch m, int l)
{
int k = m.J;
double pi = EstimateGuesses(m, password);
if (l > 1)
{
pi *= optimalPi[m.I - 1][l - 1];
}
double g = Factorial(l) * pi;
if (!excludeAdditive)
{
g += Math.Pow(minGuessesBeforeGrowingSequence, l - 1);
}
foreach (KeyValuePair <int, double> kv in optimalG[k])
{
int competingL = kv.Key;
double competingG = kv.Value;
if (competingL > l)
{
continue;
}
else if (competingG <= g)
{
return;
}
}
optimalG[k].AddOrSet(l, g);
optimalM[k].AddOrSet(l, m);
optimalPi[k].AddOrSet(l, pi);
}
void BruteforceUpdate(int k)
{
ZxcvbnMatch m = MakeBruteforceMatch(0, k);
Update(m, 1);
for (int i = 1; i <= k; i++)
{
m = MakeBruteforceMatch(i, k);
foreach (KeyValuePair <int, ZxcvbnMatch> kv in optimalM[i - 1])
{
int l = kv.Key;
ZxcvbnMatch lastM = kv.Value;
if (lastM.Pattern == MatchPattern.Bruteforce)
{
continue;
}
Update(m, l + 1);
}
}
}
ZxcvbnMatch MakeBruteforceMatch(int i, int j) => new ZxcvbnMatch
{
Pattern = MatchPattern.Bruteforce,
Token = password.Substring(i, j - i + 1),
I = i,
J = j
};
ZxcvbnMatch[] Unwind(int n)
{
List <ZxcvbnMatch> optimalMatchSequence = new List <ZxcvbnMatch>();
int k = n - 1;
int l = 0;
double g = double.PositiveInfinity;
foreach (KeyValuePair <int, double> kv in optimalG[k])
{
int candidateL = kv.Key;
double candidateG = kv.Value;
if (candidateG < g)
{
l = candidateL;
g = candidateG;
}
}
while (k >= 0)
{
ZxcvbnMatch m = optimalM[k][l];
optimalMatchSequence.Insert(0, m);
k = m.I - 1;
l--;
}
return(optimalMatchSequence.ToArray());
}
for (int k = 0; k < password.Length; k++)
{
foreach (ZxcvbnMatch m in matchesByJ[k])
{
if (m.I > 0)
{
foreach (int l in optimalM[m.I - 1].Keys.OrderBy(k => k))
{
Update(m, l + 1);
}
}
else
{
Update(m, 1);
}
}
BruteforceUpdate(k);
}
ZxcvbnMatch[] optimalMatchSequence = Unwind(password.Length);
int optimalL = optimalMatchSequence.Length;
double guesses = password.Length == 0 ? 1 : optimalG[password.Length - 1][optimalL];
return(new ZxcvbnResult
{
Password = password,
Guesses = guesses,
GuessesLog10 = Log10(guesses),
Sequence = optimalMatchSequence
});
}
private static double RepeatGuesses(ZxcvbnMatch match)
{
return(match.BaseGuesses * match.RepeatCount);
}