diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2013-12-19  Sam Truzjan  <pxqr.sta@gmail.com>
+
+	* 0.4.3.0: Add lookAhead and match functions.
+
 2013-12-16  Sam Truzjan  <pxqr.sta@gmail.com>
 
 	* 0.4.2.1: Override default Monad(fail) method so it is possible
diff --git a/bencoding.cabal b/bencoding.cabal
--- a/bencoding.cabal
+++ b/bencoding.cabal
@@ -1,5 +1,5 @@
 name:                  bencoding
-version:               0.4.2.1
+version:               0.4.3.0
 license:               BSD3
 license-file:          LICENSE
 author:                Sam Truzjan
@@ -29,7 +29,7 @@
   type:                git
   location:            git://github.com/cobit/bencoding.git
   branch:              master
-  tag:                 v0.4.2.1
+  tag:                 v0.4.3.0
 
 library
   default-language:    Haskell2010
diff --git a/src/Data/BEncode.hs b/src/Data/BEncode.hs
--- a/src/Data/BEncode.hs
+++ b/src/Data/BEncode.hs
@@ -78,11 +78,13 @@
        , Result
        , decodingError
        , fromDict
+       , lookAhead
 
        , next
        , req
        , opt
        , field
+       , match
 
        , (<$>!)
        , (<$>?)
@@ -671,6 +673,15 @@
   fail msg = Get (lift (Left msg))
   {-# INLINE fail #-}
 
+-- | Run action, but return without consuming and key\/value pair.
+-- Fails if the action fails.
+lookAhead :: Get a -> Get a
+lookAhead (Get m) = Get $ do
+  s <- get
+  r <- m
+  put s
+  return r
+
 -- | Get lexicographical successor of the current key\/value pair.
 next :: Get BValue
 next = Get (StateT go)
@@ -703,6 +714,16 @@
 field m = Get $ do
   v <- runGet m
   either throwError pure $ fromBEncode v
+
+-- | Match key with value.
+match :: BKey -> BValue -> Get ()
+match key expected = do
+  actual <- req key
+  if actual == expected
+    then return ()
+    else fail $ "key match failure(" ++ show key ++ "): " ++
+                "expected = " ++ show expected ++
+                "actual   = " ++ show actual
 
 -- | Shorthand for: @f '<$>' 'field' ('req' k)@.
 (<$>!) :: BEncode a => (a -> b) -> BKey -> Get b