cryptopals

commit ff01c61677c0e9206e7e0549fede3f3571b5c04c
parent 64357d513f00456eab1de95b0917fe73ba37aff2
Author: Jared Tobin <jared@jtobin.io>
Date:   Wed,  2 Aug 2023 09:25:12 -0230

Fix some bit rot & add CTR mode to binaries.

Diffstat:
M
docs/s3.md
 | 
10
++++++++--
M
src/AES.hs
 | 
30
+++++++++++++++++++++++++-----
M
src/MT19937.hs
 | 
2
+-

3 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/docs/s3.md b/docs/s3.md
@@ -77,8 +77,6 @@ padding oracle attack (for arbitrary ciphertexts):
 
 #### 3.18
 
-(FIXME, add binaries for these.)
-
 CTR mode is trivial; the only thing to get right is really the specified
 counter format. `Cryptopals.AES.decryptCtrAES128` (or its synonym,
 `encryptCtrAES128`) can be used to retrieve our desired plaintext:
@@ -87,6 +85,14 @@ counter format. `Cryptopals.AES.decryptCtrAES128` (or its synonym,
     > decryptCtrAES128 0 "YELLOW SUBMARINE" cip
     "Yo, VIP Let's kick it Ice, Ice, baby Ice, Ice, baby "
 
+You can get at this from the command line via the 'ctr' arg to the 'aes'
+binary:
+
+    $ ct=$(echo "L77na/nrFsKvynd6HzOoG7GHTLXsTVu9qvY/2syLXzhPweyyMTJULu/6/kXX0KSvoOLSFQ==" | base64 -d | xxd -p | tr -d '\n')
+    $ key=$(echo -n "YELLOW SUBMARINE" | xxd -p)
+    $ aes decrypt ctr --nonce 0 "$key" "$ct" | xxd -r -p
+    Yo, VIP Let's kick it Ice, Ice, baby Ice, Ice, baby
+
 #### 3.19 (and 3.20)
 
 I used the same approach as was done in question 1.6, taking the
diff --git a/src/AES.hs b/src/AES.hs
@@ -10,6 +10,7 @@ import qualified Data.Char as C
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as TE
 import qualified Data.Text.IO as TIO
+import GHC.Word (Word64)
 import qualified Options.Applicative as O
 import qualified System.Exit as SE
 import qualified System.IO as SIO
@@ -21,13 +22,15 @@ data Operation =
 data Mode =
     ECB
   | CBC
+  | CTR
 
 data Args = Args {
-    argsOpr :: Operation
-  , argsMod :: Mode
-  , argsIv  :: Maybe T.Text
-  , argsKey :: T.Text
-  , argsInp :: T.Text
+    argsOpr   :: Operation
+  , argsMod   :: Mode
+  , argsIv    :: Maybe T.Text
+  , argsKey   :: T.Text
+  , argsNonce :: Maybe Word64
+  , argsInp   :: T.Text
   }
 
 ops :: O.Parser Args
@@ -36,6 +39,7 @@ ops = Args
   <*> modeParser
   <*> optional (O.strOption (O.long "iv" <> O.metavar "IV"))
   <*> O.argument O.str (O.metavar "KEY")
+  <*> optional (O.option O.auto (O.long "nonce" <> O.metavar "NONCE"))
   <*> O.argument O.str (O.metavar "INPUT")
 
 operationParser :: O.Parser Operation
@@ -53,6 +57,7 @@ modeParser = O.argument mode etc where
   mode = O.eitherReader $ \input -> case fmap C.toLower input of
     "ecb" -> pure ECB
     "cbc" -> pure CBC
+    "ctr" -> pure CTR
     _     -> Left ("invalid mode: " <> input)
 
   etc = O.metavar "MODE"
@@ -91,6 +96,13 @@ aes Args {..} = do
               Right iv ->
                 out $ AES.encryptCbcAES128 iv k v
 
+          CTR -> case argsNonce of
+            Nothing -> do
+              err $ "cryptopals: must provide nonce"
+              SE.exitFailure
+
+            Just n -> out $ AES.encryptCtrAES128 n k v
+
         Decrypt -> case argsMod of
           ECB -> out $ AES.decryptEcbAES128 k v
 
@@ -98,6 +110,7 @@ aes Args {..} = do
             Nothing -> do
               err $ "cryptopals: must provide IV"
               SE.exitFailure
+
             Just miv -> case B16.decodeBase16 (TE.encodeUtf8 miv) of
               Left e -> do
                 err $ "cryptopals: " <> e
@@ -106,6 +119,13 @@ aes Args {..} = do
               Right iv ->
                 out $ AES.decryptCbcAES128 k v
 
+          CTR -> case argsNonce of
+            Nothing -> do
+              err $ "cryptopals: must provide nonce"
+              SE.exitFailure
+
+            Just n -> out $ AES.decryptCtrAES128 n k v
+
 main :: IO ()
 main = do
   let pars = O.info (O.helper <*> ops) $
diff --git a/src/MT19937.hs b/src/MT19937.hs
@@ -23,7 +23,7 @@ ops = Args
 mt :: Args -> IO ()
 mt Args {..} = do
   let gen        = MT.seed argsSeed
-      (bytes, _) = MT.bytes (fromIntegral argsBytes) gen
+      (bytes, _) = MT.tap (fromIntegral argsBytes) gen
 
   for_ bytes $ TIO.putStrLn . T.pack . show