private static void Update(string password, OptimalValues optimal, Match m, int l, bool excludeAdditive)
{
var k = m.j;
var pi = EstimateGuesses(m, password);
if (l > 1)
{
pi *= optimal.Pi[m.i - 1][l - 1];
}
var g = Factorial(l) * pi;
if (!excludeAdditive)
{
g += Math.Pow(MinimumGuessesBeforeGrowingSequence, l - 1);
}
foreach (var competingL in optimal.G[k].Keys)
{
var competingG = optimal.G[k][competingL];
if (competingL > l)
{
continue;
}
if (competingG <= g)
{
return;
}
}
optimal.G[k][l] = g;
optimal.M[k][l] = m;
optimal.Pi[k][l] = pi;
}
private static List <Match> Unwind(OptimalValues optimal, int n)
{
var optimalMatchSequence = new List <Match>();
var k = n - 1;
var l = -1;
var g = double.PositiveInfinity;
foreach (var candidateL in optimal.G[k].Keys)
{
var candidateG = optimal.G[k][candidateL];
if (candidateG < g)
{
l = candidateL;
g = candidateG;
}
}
while (k >= 0)
{
var m = optimal.M[k][l];
optimalMatchSequence.Insert(0, m);
k = m.i - 1;
l--;
}
return(optimalMatchSequence);
}
/// <summary>
/// Identifies the most guessable match in the sequence.
/// </summary>
/// <param name="password">The password.</param>
/// <param name="matches">The matches.</param>
/// <param name="excludeAdditive">if set to <c>true</c>, will exclude additive matches (for unit testing only).</param>
/// <returns>A summary on the most testable match.</returns>
public static MostGuessableMatchResult MostGuessableMatchSequence(string password, IEnumerable <Match> matches, bool excludeAdditive = false)
{
var matchesByJ = Enumerable.Range(0, password.Length).Select(i => new List <Match>()).ToList();
foreach (var m in matches)
{
matchesByJ[m.j].Add(m);
}
var optimal = new OptimalValues(password.Length);
for (var k = 0; k < password.Length; k++)
{
foreach (var m in matchesByJ[k])
{
if (m.i > 0)
{
foreach (var l in optimal.M[m.i - 1].Keys)
{
Update(password, optimal, m, l + 1, excludeAdditive);
}
}
else
{
Update(password, optimal, m, 1, excludeAdditive);
}
}
BruteforceUpdate(password, optimal, k, excludeAdditive);
}
var optimalMatchSequence = Unwind(optimal, password.Length);
var optimalL = optimalMatchSequence.Count;
double guesses;
if (password.Length == 0)
{
guesses = 1;
}
else
{
guesses = optimal.G[password.Length - 1][optimalL];
}
return(new MostGuessableMatchResult
{
Guesses = guesses,
Password = password,
Sequence = optimalMatchSequence,
Score = 0,
});
}
private static void BruteforceUpdate(string password, OptimalValues optimal, int k, bool excludeAdditive)
{
Update(password, optimal, MakeBruteforceMatch(password, 0, k), 1, excludeAdditive);
for (var i = 1; i <= k; i++)
{
var m = MakeBruteforceMatch(password, i, k);
var obj = optimal.M[i - 1];
foreach (var l in obj.Keys)
{
var lastM = obj[l];
if (lastM.Pattern == "bruteforce")
{
continue;
}
Update(password, optimal, m, l + 1, excludeAdditive);
}
}
}
