Exemple #1
0
        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;
        }
Exemple #2
0
        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);
        }
Exemple #3
0
        /// <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,
            });
        }
Exemple #4
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);
                }
            }
        }