matasano.scala

object Matasano {
  def hexToBytes(hex: String): Array[Byte] = {
    hex.replaceAll("[^0-9A-Fa-f]", "").sliding(2,2).toArray.map(Integer.parseInt(_, 16).toByte)
  }

  def bytesToHex(bytes: Array[Byte]): String = {
    bytes.map("%02x" format _).mkString
  }

  def encode64(b: Array[Byte]): String = {
    def sixBits(x: Array[Byte]): Array[Int] = {
      val a = (x(0) & 0xfc) >> 2
      val b = ((x(0) & 0x3) << 4) | ((x(1) & 0xf0) >> 4)
      val c = ((x(1) & 0xf) << 2) | ((x(2) & 0xc0) >> 6)
      val d = (x(2)) & 0x3f
      Array(a, b, c, d)
    }
    val zero = Array(0, 0).map(_.toByte)
    val pad = (3 - b.length % 3) % 3
    val encodeTable = ('A' to 'Z') ++ ('a' to 'z') ++ ('0' to '9') ++ Seq('+', '/')
    ((b ++ zero.take(pad)).grouped(3)
      .flatMap(sixBits)
      .map(encodeTable)
      .toArray
      .dropRight(pad) :+ "="*pad)
      .mkString
  }

  def fixedXOR(hex: String, xor: String): String = {
    bytesToHex(hexToBytes(hex).zip(hexToBytes(xor)).map((t) => t._1 ^ t._2).map(_.toByte))
  }

  def singleByteXOR(cipherText: String): Array[String] = {
    val cipherByteArray = hexToBytes(cipherText)
    (('A' to 'Z') ++ ('a' to 'z')).toArray.map((char) =>
      new String(cipherByteArray.zip(Array.fill(cipherByteArray.length)(char)).map((t) => t._2 ^ t._1).map(_.toByte), "UTF-8")
    )
  }

  def main(args: Array[String]) {
    // Test hex/base64
    assert(
      encode64(hexToBytes("49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d")) ==
      "SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t"
    )

    // Test fixed-length XOR
    assert(
      fixedXOR("1c0111001f010100061a024b53535009181c", "686974207468652062756c6c277320657965") ==
      "746865206b696420646f6e277420706c6179"
    )

    singleByteXOR("1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736").map(println)
  }

}