A little algorithm using genetic concepts to find a secret word.

.gitignore

out/*

whatIsTheSecretWord.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

__author__ = "Ademar Alves de Oliveira"
__copyright__ = "Copyright 2014, Ademar"
__credits__ = ["Diego Queiroz"]
__license__ = "GPL"
__version__ = "1.5"
__maintainer__ = "Ademar Alves"
__email__ = "[email protected]"

from random import random, choice, randint
from collections import OrderedDict
 
class witsw:
	
	#variables to be changed
	maxWordSize = 1000 #the max size of the word
	populationSize = 100 #the size of the population
	populationToCrossOver = 10 #the number of qualified to reproduction
	mutationRate = 0.01 #the mutation rate
	generationsLimite = 0 #max number of generations, 0 no limit
	minSimilarity = 0 #min similarity target to stop
	secretWord = "Top Secret" #the word to be founded, use only python asc characters! and the len need be equal or minor then maxWordSize. Set empty to generate a randow secret word with maxWordSize size
	
	#script variables
	letters = []
	population = []
	
	def __init__(self):
		if(len(self.secretWord) == 0):
			for i in range(self.maxWordSize):
				self.secretWord += chr(int(random() * 256))
			print "random secret word is %s" % (self.secretWord)
		
		for letter in range(256):
			self.letters.append(chr(letter))
		for i in range(self.populationSize):
			self.population.append(self.makeRandomWord())
	
	def makeRandomWord(self):
		wordSize = int(self.maxWordSize * random())
		randomWord = ""
		for w in range(wordSize):
			randomWord += choice(self.letters)
		return randomWord
	
	def pontualizeWord(self, word):
		diff = abs(len(self.secretWord) - len(word)) * 255
		for i in range(min(len(self.secretWord), len(word))):
			diff += self.getBitDifference(ord(self.secretWord[i]), ord(word[i]))
		return diff
 
	def getBitDifference(self, numA, numB):
		diff = 0
		numC = numA ^ numB
		while numC > 0:
			diff += numC % 2
			numC /= 2
		return diff
 
	def rankPopulation(self):
		classificationMap = {}	
		for p in self.population:
			classificationMap[p] = self.pontualizeWord(p)
		classificationMap = OrderedDict(sorted(classificationMap.items(), key=lambda t: t[1]))
		self.population = classificationMap.keys()
		return classificationMap.values()
	
	def makeNewGeneration(self):
		betters = self.population[:self.populationToCrossOver]
		self.population  = [b for b in betters]
		while len(self.population) < self.populationSize:
			for b1 in betters:
				for b2 in betters:
					self.population.append(self.crossover(betters[int(random()*self.populationToCrossOver)], betters[int(random()*self.populationToCrossOver)]))
					if len(self.population) >= self.populationSize:
						return
	
	def crossover(self, father, mother):
		#make a children
		lenMin = min(len(father), len(mother))
		children = []
		for i in range(lenMin):
			if self.mutationRate >= random(): #do a mutation
				children.append(chr(randint(0,255)))
			else:
				randomMask = randint(0,255)
				children.append(chr((ord(father[i]) & randomMask) | (ord(mother[i]) & ~randomMask)))
		#change the word size with mutation
		if self.mutationRate >= random() and lenMin > 0:
			mutatioType = random()
			if mutatioType < 0.5: #type add letter
				pos = int(random() * lenMin)
				if pos >= lenMin: #add on end
					children.append(chr(int(random() * 256)))
				else: #add on middle or begin
					children.append(children[pos])
					children[pos] = chr(int(random() * 256))
			else: #type delete a letter
				del children[int(random() * lenMin)]
		#return the children as String
		return ''.join(children)
	
	def run(self):
		temp = None
		if self.generationsLimite <= 0:
			generation = 0
			while not temp:
				generation += 1
				temp = self.runGeneration(generation)
		else:
			for generation in range(self.generationsLimite):
				temp = self.runGeneration(generation)
				if temp:
					break
		return temp
	
	def runGeneration(self, generation):
		rank = self.rankPopulation()
		print "better at generation %d is \"%s\" with %d points" % (generation, self.population[0], rank[0])
		if rank[0] <= self.minSimilarity:
			return self.population[0]
		self.makeNewGeneration()
		return None
 
print "The Secret word is %s" % (witsw().run())

To run download the script and run on console:

python whatIsTheSecretWord.py

Try change the secretWord variable, and the others variables too.