Challenge 7

1 files changed, 85 insertions, 0 deletions

diff --git a/test/Set1Spec.scala b/test/Set1Spec.scala
index 628889c..b017803 100644
--- a/test/Set1Spec.scala
+++ b/test/Set1Spec.scala
@@ -6,6 +6,7 @@ class Set1Spec extends IxeeSpec {
 
   import ixee.cryptopals.utils.ConversionUtils._
   import ixee.cryptopals.utils.ByteUtils._
+  import ixee.cryptopals.utils.StreamUtils._
   import ixee.cryptopals.solvers._
 
   "Set1" - {
@@ -46,6 +47,90 @@ class Set1Spec extends IxeeSpec {
           (("Now that the party is jumping\n", 170))
       }
     }
+
+    "Challenge 5: repeating-key xor" - {
+      val sourceText = """|Burning 'em, if you ain't quick and nimble
+                          |I go crazy when I hear a cymbal""".stripMargin
+
+      val key = "ICE"
+
+      val ciphertext =
+        sourceText.asBytes.to[Stream] xor key.asBytes.to[Stream].continually
+
+      ciphertext.hex mustBe(
+        Seq(
+          "0b3637272a2b2e63622c2e69",
+          "692a23693a2a3c6324202d62",
+          "3d63343c2a26226324272765",
+          "272a282b2f20430a652e2c65",
+          "2a3124333a653e2b2027630c",
+          "692b20283165286326302e27",
+          "282f"
+        ).mkString("")
+      )
+    }
+
+    "Challenge 6: break repeating-key xor" - {
+
+      "hamming distance should be computed correctly" in {
+
+        val textA = "this is a test"
+        val textB = "wokka wokka!!!"
+
+        hammingDistance(textA, textB) mustBe 37
+
+      }
+
+      "prioritizes likely key sizes" in {
+
+        val sourceText =
+          """|the quick brown fox jumps over the lazy dog
+             |This code is going to turn out to be surprisingly useful later on.
+             |Breaking repeating-key XOR ("Vigenere") statistically is obviously
+             | an academic exercise, a "Crypto 101" thing. But more people "know
+             | how" to break it than can actually break it, and a similar
+             | technique breaks something much more important.""".stripMargin.replace("\n", "")
+
+        val key = "ICE IS REALLY NICE"
+
+        val ciphertext = sourceText.asByteStream xor key.asByteStream.continually
+
+        val expectedKeySize = XorDecrypt.inferKeySize(ciphertext)
+
+        expectedKeySize mustBe key.length
+
+      }
+
+      "cracks multi-byte keys" in {
+        val sourceText =
+          """|the quick brown fox jumps over the lazy dog
+             |This code is going to turn out to be surprisingly useful later on.
+             |Breaking repeating-key XOR statistically is obviously
+             | an academic exercise, a "Crypto 101" thing. But more people "know
+             | how" to break it than can actually break it, and a similar
+             | technique breaks something much more important.""".stripMargin.replace("\n", "")
+
+        val key = "ICE IS REALLY NICE"
+
+        val ciphertext = sourceText.asByteStream xor key.asByteStream.continually
+
+        XorDecrypt.findBestMultiByteKey(ciphertext).take(key.length).asAscii mustBe key
+
+        XorDecrypt.crackForMultiByteKey(ciphertext) mustBe sourceText
+      }
+
+      "cracks the challenge text" in {
+
+        Challenge6.run mustBe Challenge6.expectation
+
+      }
+    }
+
+    "Challenge 7: AES/ECB mode" in {
+
+      Challenge7.run mustBe Challenge6.expectation
+
+    }
   }
 
 }