diff --git a/HsOpenSSL.cabal b/HsOpenSSL.cabal
--- a/HsOpenSSL.cabal
+++ b/HsOpenSSL.cabal
@@ -5,7 +5,7 @@
         can generate RSA and DSA keys, read and write PEM files,
         generate message digests, sign and verify messages, encrypt
         and decrypt messages.
-Version: 0.6.2
+Version: 0.6.3
 License: PublicDomain
 License-File: COPYING
 Author: Adam Langley <agl at imperialviolet.org>, PHO <pho at cielonegro.org>
@@ -44,7 +44,6 @@
       CPP-Options:        -DCALLCONV=stdcall
   else
       Extra-Libraries: crypto ssl
-      build-depends:      unix >= 2.3.0.0
       C-Sources:          cbits/mutex-pthread.c
       CC-Options:         -D PTHREAD
       CPP-Options:        -DCALLCONV=ccall
diff --git a/NEWS b/NEWS
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,20 @@
 -*- Coding: utf-8 -*-
 
+Changes from 0.6.2 to 0.6.3
+---------------------------
+* Suggestion by Grant Monroe:
+
+  - Changed the signature of OpenSSL.EVP.Sign.signBS from
+      signBS :: KeyPair key => Digest -> key -> Strict.ByteString -> IO String
+    to
+      signBS :: KeyPair key => Digest -> key -> Strict.ByteString -> IO Strict.ByteString
+
+  - Changed the signature of OpenSSL.EVP.Sign.signLBS from
+      signLBS :: KeyPair key => Digest -> key -> Lazy.ByteString -> IO String
+    to
+      signLBS :: KeyPair key => Digest -> key -> Lazy.ByteString -> IO Lazy.ByteString
+
+
 Chanegs from 0.6.1 to 0.6.2
 ---------------------------
 * Applied a patch by John Van Enk and his friend:
diff --git a/OpenSSL/EVP/Sign.hsc b/OpenSSL/EVP/Sign.hsc
--- a/OpenSSL/EVP/Sign.hsc
+++ b/OpenSSL/EVP/Sign.hsc
@@ -46,24 +46,26 @@
      -> String    -- ^ input string
      -> IO String -- ^ the result signature
 sign md pkey input
-    = signLBS md pkey $ L8.pack input
+    = liftM L8.unpack $ signLBS md pkey $ L8.pack input
 
 -- |@'signBS'@ generates a signature from a chunk of data.
 signBS :: KeyPair key =>
           Digest     -- ^ message digest algorithm to use
        -> key        -- ^ private key to sign the message digest
        -> B8.ByteString -- ^ input string
-       -> IO String  -- ^ the result signature
+       -> IO B8.ByteString -- ^ the result signature
 signBS md pkey input
     = do ctx <- digestStrictly md input
-         signFinal ctx pkey
+         sig <- signFinal ctx pkey
+         return $ B8.pack sig
 
 -- |@'signLBS'@ generates a signature from a stream of data.
 signLBS :: KeyPair key =>
            Digest        -- ^ message digest algorithm to use
         -> key           -- ^ private key to sign the message digest
         -> L8.ByteString -- ^ input string
-        -> IO String     -- ^ the result signature
+        -> IO L8.ByteString -- ^ the result signature
 signLBS md pkey input
     = do ctx <- digestLazily md input
-         signFinal ctx pkey
+         sig <- signFinal ctx pkey
+         return $ L8.pack sig