Isolate crypto

Also add in a salt generator

source/Crypto.elm

@@ -0,0 +1,109 @@
+port module Crypto exposing (..)
+
+import Random exposing (Generator)
+import Array exposing (Array)
+import List exposing (map)
+import Dict
+import String
+import Bitwise exposing (and, shiftRightBy)
+
+-- Hashing
+
+-- Port for sending out data to be hashed
+port sha256 : String -> Cmd msg
+
+-- Port for listening to hashed messages
+port sha_result : (String -> msg) -> Sub msg
+
+-- Monoalphabetic Substitution
+type alias MaskStep = (Array Char, Int)
+
+-- Alphabetical characters
+alphas = String.toList (String.toUpper "abcdefghijklmnopqrstuvwxyz")
+numAlphas = List.length alphas
+
+-- Letter shuffling
+swapLetters : Array Char -> Int -> Int -> Array Char
+swapLetters chars a b =
+    let
+        letterA = Array.get a chars |> Maybe.withDefault '?'
+        letterB = Array.get b chars |> Maybe.withDefault '?'
+    in
+        chars |> Array.set a letterB |> Array.set b letterA
+
+-- String shuffling generator
+genMask : MaskStep -> Generator MaskStep
+genMask step = 
+    let 
+        (mask, next) = step
+        alphaInt = Random.int 0 (numAlphas - 1)
+        fromInt i =
+            ( swapLetters mask next i
+            , next + 1
+            )
+    in
+        Random.map fromInt alphaInt 
+
+-- Continue to next step of mask generation
+stepMask : (MaskStep -> msg) -> MaskStep -> Cmd msg
+stepMask message step =
+    let
+        (_, count) = step
+    in
+        if (count >= numAlphas) then
+            Cmd.none
+        else
+            Random.generate message (genMask step)
+
+-- Start generating a mash
+newMask : (MaskStep -> msg) -> Cmd msg
+newMask message = 
+    stepMask message (Array.fromList alphas, 0)
+
+-- Apply a substitution mask on the message
+substitute : MaskStep -> String -> String
+substitute step text =
+    let
+        (mask, _) = step
+        zip a b =
+            case (List.head a) of
+                Nothing -> []
+                Just a_head ->
+                    case (List.head b) of
+                        Nothing -> []
+                        Just b_head -> 
+                            (a_head, b_head) :: zip 
+                                (Maybe.withDefault [] (List.tail a))
+                                (Maybe.withDefault [] (List.tail b))
+        maskDict = mask |> Array.toList |> zip alphas |> Dict.fromList
+        subChar c = Dict.get c maskDict |> Maybe.withDefault c
+    in
+        map subChar (String.toList text) |> String.fromList
+
+-- Encode an int as hex
+hexchars : Array Char
+hexchars = 
+    "0123456789abcdef"
+    |> String.toList
+    |> Array.fromList
+
+hexEncode : Int -> String
+hexEncode value =
+    let
+        tail = and value 15
+        char = Array.get tail hexchars |> Maybe.withDefault '0'
+        init = shiftRightBy 4 value
+    in
+        if (value /= 0) then
+            char |> String.fromChar |> (++) (hexEncode init)
+        else
+            ""
+
+-- Generate a salt
+genSalt : (String -> msg) -> Cmd msg
+genSalt message =
+    let
+        saltGenerator =
+            Random.map hexEncode (Random.int Random.minInt Random.maxInt)
+    in
+        Random.generate message saltGenerator

source/Data.elm

@@ -1,7 +1,7 @@
 -- Data structures
 module Data exposing (..)
 
-import Sha exposing (..)
+import Crypto exposing (..)
 import Dict exposing (Dict, get)
 import Keyboard
 import Char
@@ -37,54 +37,11 @@ type alias Model =
     , hash : String
     }
 
--- Alphabetical characters
-alphas = String.toList (String.toUpper "abcdefghijklmnopqrstuvwxyz")
-numAlphas = List.length alphas
-
-swapLetters : Array Char -> Int -> Int -> Array Char
-swapLetters chars a b =
-    let
-        letterA = Array.get a chars |> Maybe.withDefault '?'
-        letterB = Array.get b chars |> Maybe.withDefault '?'
-    in
-        chars |> Array.set a letterB |> Array.set b letterA
-
--- String shuffling generator
-genMask : Array Char -> Int -> Generator (Array Char, Int)
-genMask mask next = 
-    let 
-        alphaInt = Random.int 0 (numAlphas - 1)
-        fromInt i =
-            ( swapLetters mask next i
-            , next + 1
-            )
-    in
-        Random.map fromInt alphaInt 
-
--- Apply a substitution on the message
-substitute : List Char -> String -> String
-substitute mask text =
-    let
-        zip a b =
-            case (List.head a) of
-                Nothing -> []
-                Just a_head ->
-                    case (List.head b) of
-                        Nothing -> []
-                        Just b_head -> 
-                            (a_head, b_head) :: zip 
-                                (Maybe.withDefault [] (List.tail a))
-                                (Maybe.withDefault [] (List.tail b))
-        maskDict = zip alphas mask |> Dict.fromList
-        subChar c = Dict.get c maskDict |> Maybe.withDefault c
-    in
-        map subChar (String.toList text) |> String.fromList
-
-messageSubstitute : Array Char -> List String -> List String
-messageSubstitute mask message =
+messageSubstitute : MaskStep -> List String -> List String
+messageSubstitute step message =
     message
     |> String.join " "
-    |> substitute (Array.toList mask)
+    |> substitute step
     |> String.words
 
 
@@ -112,7 +69,7 @@ init flags  =
         flags.hash 
         flags.salt
         "" 
-    , Random.generate GenMask (genMask (Array.fromList alphas) 0)
+    , newMask GenMask
     )
 
 -- Initial Map
@@ -152,11 +109,10 @@ update msg model =
             ( { model | hash = h }
             , Cmd.none
             )
-        GenMask (mask, next) ->
-            if (next >= numAlphas) then
-                ({ model | message = messageSubstitute mask model.message}, Cmd.none)
-            else 
-                (model, Random.generate GenMask (genMask mask next))
+        GenMask step ->
+            ( { model | message = messageSubstitute step model.message}
+            , stepMask GenMask step 
+            )
 
 -- Get a hash of the current decode
 decodeCheck : Model -> Cmd Msg
@@ -178,6 +134,6 @@ subscriptions msg =
     in
         Sub.batch
             [ Keyboard.presses pressMessage
-            , Sha.sha_result Hash
+            , Crypto.sha_result Hash
             ]
 

source/Main.elm

@@ -1,6 +1,4 @@
 -- NSA Crypto App
-
-import Sha exposing (..)
 import Data exposing (init, update, subscriptions)
 import Display exposing (view)
 import Html exposing (programWithFlags)