From d32466d20399489ae5cf254588c87e009a9c29f7 Mon Sep 17 00:00:00 2001
From: iximeow <me@iximeow.net>
Date: Sun, 23 Nov 2014 18:56:24 -0800
Subject: Add challenge 4

---
 src/solvers/XorDecrypt.scala | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

(limited to 'src/solvers/XorDecrypt.scala')

diff --git a/src/solvers/XorDecrypt.scala b/src/solvers/XorDecrypt.scala
index b7f7c43..6b82c34 100644
--- a/src/solvers/XorDecrypt.scala
+++ b/src/solvers/XorDecrypt.scala
@@ -2,18 +2,24 @@ package ixee.cryptopals.solvers
 
 import ixee.cryptopals.utils._
 import ixee.cryptopals.utils.ByteUtils._
+import ixee.cryptopals.utils.FunctionUtils._
 
 object XorDecrypt {
   implicit val freq = Frequencies.cornell40kSample
 
-  def tryBestDecrypt(ciphertext: Seq[Byte]) = {
-    val key = findBestSingleByteKey(ciphertext)
+  def decryptToAscii(ciphertext: Seq[Byte])(key: Byte): String = {
     new String((ciphertext xor Stream.continually(key)).toArray)
   }
 
+  def tryBestDecrypt(ciphertext: Seq[Byte]): String = {
+    (findBestSingleByteKey _ :| decryptToAscii(ciphertext) _)(ciphertext)
+  }
+
   def findBestSingleByteKey(ciphertext: Seq[Byte]): Byte =
     candidates(ciphertext)
-      .minBy(_._1)._2.toByte
+      .reduceOption( (a: (Double, Int), b: (Double, Int)) =>
+        if (a._1 < b._1) a else b
+      ).map(_._2.toByte).getOrElse(0.toByte)
 
   def candidates(ciphertext: Seq[Byte]) =
     (0 until 256)
-- 
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