all possible solutions generator, can be used to brute force passwords, hashes, ... / published by https://github.com/dacr/code-examples-manager #768484fa-7034-4e6d-9c7e-598d2bc8673a/4f22ce93d4a3f9529ae3b4cbdea67f6dc7fae243

algo-solution-brute-force.sc

// summary : all possible solutions generator, can be used to brute force passwords, hashes, ...
// keywords : scala, algorithm, bruteforce, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 768484fa-7034-4e6d-9c7e-598d2bc8673a
// created-on : 2020-04-07T20:29:03Z
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.3.0"
//> using dep "org.scalatest::scalatest:3.2.16"
//> using objectWrapper
// ---------------------

import org.scalatest._, flatspec._, matchers._

type Fragment = Byte
type Solution = Array[Fragment]


case class Alphabet(fragments: Array[Fragment]) {
  val size = fragments.size
  def head:Fragment = fragments.head
  def apply(index: Int):Fragment = fragments(index)
}


case class SolutionContext(
  solutionLength: Int,
  alphabet: Alphabet) {
  def possibleSolutionsCount():BigInt = BigInt(alphabet.size).pow(solutionLength)
}


case class SolutionGenerator(context: SolutionContext)  {
  def generator(): Iterator[Solution] = {
    val currentSolutionAlphabetIndices = Array.fill(context.solutionLength)(0)
    def inc(): Boolean = {
      @annotation.tailrec
      def incworker(position: Int): Boolean = {
        if (position == context.solutionLength) false else {
          if (currentSolutionAlphabetIndices(position) < context.alphabet.size - 1) {
            currentSolutionAlphabetIndices(position) +=  1
            true
          } else {
            currentSolutionAlphabetIndices(position) = 0
            incworker(position + 1)
          }
        }
      }
      incworker(0)
    }
    new Iterator[Solution] {
      private var status: Boolean = true
      def hasNext: Boolean = status
      def next(): Solution = {
        val newone = Array.ofDim[Byte](context.solutionLength)
        for(i <- 0 until context.solutionLength) newone(i)=context.alphabet(currentSolutionAlphabetIndices(i))
        status = inc()
        newone
      }
    }
  }
}


class GeneratorTest extends AnyFlatSpec with should.Matchers {
  override def suiteName: String = "GeneratorTest"

  "SolutionGenerator" should "generates the right possible solutions" in {
    val context = SolutionContext(2, Alphabet(Array('a', 'b')))
    val generator = SolutionGenerator(context).generator()
    context.possibleSolutionsCount() shouldBe 4
    generator.toList.map(_.map(_.toChar).mkString) shouldBe List("aa", "ba", "ab", "bb")
  }
}

org.scalatest.tools.Runner.main(Array("-oDF", "-s", classOf[GeneratorTest].getName))