March 2014 update

Task/Vigen-re-cipher/Scala/vigen-re-cipher-2.scala

@@ -0,0 +1,52 @@
+class Vigenere(val key: String) {
+
+  private def rotate(p: Int, s: IndexedSeq[Char]) = s.drop(p) ++ s.take(p)
+
+  private val chars = 'A' to 'Z'
+
+  private val vSquare = (chars ++
+                rotate(1, chars) ++
+                rotate(2, chars) ++
+                rotate(3, chars) ++
+                rotate(4, chars) ++
+                rotate(5, chars) ++
+                rotate(6, chars) ++
+                rotate(7, chars) ++
+                rotate(8, chars) ++
+                rotate(9, chars) ++
+                rotate(10, chars) ++
+                rotate(11, chars) ++
+                rotate(12, chars) ++
+                rotate(13, chars) ++
+                rotate(14, chars) ++
+                rotate(15, chars) ++
+                rotate(16, chars) ++
+                rotate(17, chars) ++
+                rotate(18, chars) ++
+                rotate(19, chars) ++
+                rotate(20, chars) ++
+                rotate(21, chars) ++
+                rotate(22, chars) ++
+                rotate(23, chars) ++
+                rotate(24, chars) ++
+                rotate(25, chars))
+
+  private var encIndex = -1
+  private var decIndex = -1
+
+  def encode(c: Char) = {
+    encIndex += 1
+    if (encIndex == key.length) encIndex = 0
+    if (chars.contains(c)) vSquare((c - 'A') * 26 + key(encIndex) - 'A') else c
+  }
+
+  def decode(c: Char) = {
+    decIndex += 1
+    if (decIndex == key.length) decIndex = 0
+    if (chars.contains(c)) {
+      val baseIndex = (key(decIndex) - 'A') * 26
+      val nextIndex = vSquare.indexOf(c, baseIndex)
+      chars(nextIndex - baseIndex)
+    } else c
+  }
+}

Task/Vigen-re-cipher/Scala/vigen-re-cipher-3.scala

@@ -0,0 +1,6 @@
+val text = "ATTACKATDAWN"
+val myVigenere = new Vigenere("LEMON")
+val encoded = text.map(c => myVigenere.encode(c))
+println("Plaintext => " + text)
+println("Ciphertext => " + encoded)
+println("Decrypted => " + encoded.map(c => myVigenere.decode(c)))