public CharactersFrequencyModel CalculateCharactersFrequency(string text)
{
CharactersFrequencyModel model = new CharactersFrequencyModel();
foreach (var character in text)
{
if (char.IsLetter(character))
{
if (!model.CharactersCount.ContainsKey(character))
{
model.CharactersCount[character] = 0;
}
model.CharactersCount[character]++;
model.TotalCharactersCount++;
}
}
foreach (var letter in model.CharactersCount.Keys)
{
model.CharactersFrequency[letter] = Math.Round((model.CharactersCount[letter] / model.TotalCharactersCount * 100), roundDecimalsCount);
}
model.CharactersCount.OrderBy(x => x.Key);
model.CharactersFrequency.OrderBy(x => x.Key);
return(model);
}
public Dictionary <int, string> FindKey(CharactersFrequencyModel realCharactersFrequency, string encryptedText, int n)
{
var encryptedTextModel = this.calculationsService.CalculateCharactersFrequency(encryptedText);
var iterationsCount = Math.Min(n, this.Letters.Count);
var realTextLetters = realCharactersFrequency.CharactersCount.OrderByDescending(x => x.Value).Take(iterationsCount).Select(x => x.Key);
var encryptedTextLetters = encryptedTextModel.CharactersCount.OrderByDescending(x => x.Value).Take(iterationsCount).Select(x => x.Key);
Dictionary <int, int> keysFrequency = new Dictionary <int, int>();
foreach (var realTextLetter in realTextLetters)
{
foreach (var encryptedTextLetter in encryptedTextLetters)
{
var key = (this.Letters.IndexOf(encryptedTextLetter) - this.Letters.IndexOf(realTextLetter) + this.Letters.Count) % this.Letters.Count;
if (!keysFrequency.ContainsKey(key))
{
keysFrequency[key] = 1;
}
else
{
keysFrequency[key]++;
}
}
}
var keys = keysFrequency.OrderByDescending(x => x.Value).Select(x => x.Key);
var results = new Dictionary <int, string>();
foreach (var key in keys)
{
var text = this.Decrypt(encryptedText, key);
results.Add(key, text);
}
return(results);
}
