Begin implementing HKDF

Implement the `extract` phase of HKDF.

2 files changed, 77 insertions, 1 deletions

diff --git a/tests/Codec/Crypto/HKDFTests.hs b/tests/Codec/Crypto/HKDFTests.hs
new file mode 100644
index 0000000..5daffdb
--- /dev/null
+++ b/tests/Codec/Crypto/HKDFTests.hs
@@ -0,0 +1,74 @@
+-- Copyright 2018 Google LLC
+--
+-- Licensed under the Apache License, Version 2.0 (the "License"); you may not
+-- use this file except in compliance with the License. You may obtain a copy of
+-- the License at
+--
+--     https://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+-- License for the specific language governing permissions and limitations under
+-- the License.
+
+{-# LANGUAGE OverloadedStrings #-}
+
+module Codec.Crypto.HKDFTests (tests) where
+
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as ByteString
+import qualified Data.ByteString.Base16 as ByteString.Base16
+import qualified Data.ByteString.Char8 as ByteString.Char8
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.HUnit ((@?=), testCase)
+
+import Codec.Crypto.HKDF (Salt(Salt), SecretKey(SecretKey))
+import qualified Codec.Crypto.HKDF as HKDF
+import Data.Digest (sha1, sha256)
+
+tests :: TestTree
+tests = testGroup "Codec.Crypto.HKDF" [testRFC5869]
+
+-- | Tests from RFC 5869.
+testRFC5869 = testGroup "RFC 5869 examples"
+  [ t "test case 1"
+      sha256
+      (SecretKey $ ByteString.replicate 22 0x0b)
+      (Salt $ ByteString.pack [0x00 .. 0x0c])
+      (SecretKey $ hex "077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5")
+  , t "test case 2"
+      sha256
+      (SecretKey $ ByteString.pack [0x00 .. 0x4f])
+      (Salt $ ByteString.pack [0x60 .. 0xaf])
+      (SecretKey $ hex "06a6b88c5853361a06104c9ceb35b45cef760014904671014a193f40c15fc244")
+  , t "test case 3"
+      sha256
+      (SecretKey $ ByteString.replicate 22 0x0b)
+      (Salt "")
+      (SecretKey $ hex "19ef24a32c717b167f33a91d6f648bdf96596776afdb6377ac434c1c293ccb04")
+  , t "test case 4"
+      sha1
+      (SecretKey $ ByteString.replicate 11 0x0b)
+      (Salt $ ByteString.pack [0x00 .. 0x0c])
+      (SecretKey $ hex "9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243")
+  , t "test case 5"
+      sha1
+      (SecretKey $ ByteString.pack [0x00 .. 0x4f])
+      (Salt $ ByteString.pack [0x60 .. 0xaf])
+      (SecretKey $ hex "8adae09a2a307059478d309b26c4115a224cfaf6")
+  , t "test case 6"
+      sha1
+      (SecretKey $ ByteString.replicate 22 0x0b)
+      (Salt "")
+      (SecretKey $ hex "da8c8a73c7fa77288ec6f5e7c297786aa0d32d01")
+  ]
+  where
+    t name hash ikm salt prk =
+      testGroup name [testCase "extract" $ HKDF.extract hash salt ikm @?= prk]
+
+hex :: ByteString -> ByteString
+hex s =
+  case ByteString.Base16.decode s of
+    (r, "") -> r
+    _ -> error $ "invalid hex string " ++ ByteString.Char8.unpack s
diff --git a/tests/Tests.hs b/tests/Tests.hs
index ee38f2a..6555cf3 100644
--- a/tests/Tests.hs
+++ b/tests/Tests.hs
@@ -18,11 +18,13 @@ module Main
 
 import Test.Tasty (defaultMain, testGroup)
 
+import qualified Codec.Crypto.HKDFTests
 import qualified Data.DigestTests
 import qualified Data.HMACTests
 
 main :: IO ()
 main = defaultMain $ testGroup "btls"
-  [ Data.DigestTests.tests
+  [ Codec.Crypto.HKDFTests.tests
+  , Data.DigestTests.tests
   , Data.HMACTests.tests
   ]