genetic

commit e700eba136d4dabc9a9bbe120247e78bb2f913b5
parent 9a8057c89c98eb8cc4398b412a4c7b7f253ae381
Author: dracuxan <[email protected]>
Date:   Wed,  8 Apr 2026 14:04:37 +0530

problem: breaking xor cipher

Diffstat:
A
genetic/scripts/codebreaker.exs
 | 
46
++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 46 insertions(+), 0 deletions(-)
diff --git a/genetic/scripts/codebreaker.exs b/genetic/scripts/codebreaker.exs
@@ -0,0 +1,46 @@
+defmodule Codebreaker do
+  alias Types.Chromosome
+  @behaviour Problem
+  @max_n 64
+  import Bitwise
+
+  def genotype do
+    genes = Enum.map(1..@max_n, fn _ -> Enum.random(0..1) end)
+    %Chromosome{genes: genes, size: @max_n}
+  end
+
+  def fitness_function(chromosome) do
+    target = "ILoveGeneticAlgorithms"
+    encrypted = "LIjs`B`k`qlfDibjwlqmhv"
+
+    cypher = fn word, key ->
+      word
+      |> to_charlist()
+      |> Enum.map(fn x -> rem(bxor(x, key), 32768) end)
+    end
+
+    key =
+      chromosome.genes
+      |> Enum.map(&Integer.to_string(&1))
+      |> Enum.join("")
+      |> String.to_integer(2)
+
+    guess = List.to_string(cypher.(encrypted, key))
+    String.jaro_distance(target, guess)
+  end
+
+  def terminate?(population, _generation) do
+    best = hd(population)
+    best.fitness == 1
+  end
+end
+
+{soln, _} = Genetic.run(Codebreaker, crossover_type: &Toolbox.Crossover.single_point/3)
+
+{key, ""} =
+  soln.genes
+  |> Enum.map(&Integer.to_string(&1))
+  |> Enum.join("")
+  |> Integer.parse(2)
+
+IO.puts("\nThe key is #{key}")