diff --git a/gnupg/gnupg.py b/gnupg/gnupg.py
index 9aa8232..9075e13 100644
--- a/gnupg/gnupg.py
+++ b/gnupg/gnupg.py
@@ -36,13 +36,7 @@ import os
 import re
 import textwrap
 
-try:
-    from io import StringIO
-except ImportError:
-    from cStringIO import StringIO
-
 #: see :pep:`328` http://docs.python.org/2.5/whatsnew/pep-328.html
-from .         import _parsers
 from .         import _util
 from .         import _trust
 from ._meta    import GPGBase
@@ -284,15 +278,13 @@ class GPG(GPGBase):
         signatures. If using detached signatures, the file containing the
         detached signature should be specified as the ``sig_file``.
 
-        :param file file: A file descriptor object. Its type will be checked
-            with :func:`_util._is_file`.
+        :param file file: A file descriptor object.
 
         :param str sig_file: A file containing the GPG signature data for
             ``file``. If given, ``file`` is verified via this detached
-            signature.
+            signature. Its type will be checked with :func:`_util._is_file`.
         """
 
-        fn = None
         result = self._result_map['verify'](self)
 
         if sig_file is None:
@@ -307,19 +299,15 @@ class GPG(GPGBase):
                 return result
             log.debug('verify_file(): Handling detached verification')
             sig_fh = None
-            data_fh = None
             try:
                 sig_fh = open(sig_file, 'rb')
-                data_fh = open(file, 'rb')
                 args = ["--verify %s -" % sig_fh.name]
                 proc = self._open_subprocess(args)
-                writer = _util._threaded_copy_data(data_fh, proc.stdin)
+                writer = _util._threaded_copy_data(file, proc.stdin)
                 self._collect_output(proc, result, writer, stdin=proc.stdin)
             finally:
                 if sig_fh and not sig_fh.closed:
                     sig_fh.close()
-                if data_fh and not data_fh.closed:
-                    data_fh.close()
         return result
 
     def import_keys(self, key_data):
diff --git a/gnupg/test/test_gnupg.py b/gnupg/test/test_gnupg.py
index 46876f5..bfd91c2 100755
--- a/gnupg/test/test_gnupg.py
+++ b/gnupg/test/test_gnupg.py
@@ -33,10 +33,8 @@ from glob       import glob
 from time       import localtime
 from time       import mktime
 
-import encodings
 import doctest
 import io
-import logging
 import os
 import shutil
 import sys
@@ -192,7 +190,9 @@ class GPGTestCase(unittest.TestCase):
         print(fixed)
         test_file = os.path.join(_files, 'cypherpunk_manifesto')
         self.assertTrue(os.path.isfile(test_file))
-        has_shell = self.gpg.verify_file(test_file, fixed)
+        datafd = open(test_file, 'rb')
+        has_shell = self.gpg.verify_file(datafd, sig_file=fixed)
+        datafd.close()
         self.assertFalse(has_shell.valid)
 
     def test_parsers_fix_unsafe_semicolon(self):
@@ -664,6 +664,7 @@ class GPGTestCase(unittest.TestCase):
         sig = self.gpg.sign(message, default_key=key.fingerprint,
                             passphrase='johanborst')
         self.assertTrue(sig, "Good passphrase should succeed")
+
         try:
             file = _util._make_binary_stream(sig.data, self.gpg._encoding)
             verified = self.gpg.verify_file(file)
@@ -696,7 +697,7 @@ class GPGTestCase(unittest.TestCase):
         datafd.seek(0)
         sigfd.seek(0)
 
-        verified = self.gpg.verify_file(datafn, sigfn)
+        verified = self.gpg.verify_file(datafd, sig_file=sigfn)
 
         if key.fingerprint != verified.fingerprint:
             log.warn("key fingerprint:      %r", key.fingerprint)
@@ -707,7 +708,7 @@ class GPGTestCase(unittest.TestCase):
             os.unlink(sigfn)
 
     def test_signature_verification_detached_binary(self):
-        """Test that detached signature verification in binary mode fails."""
+        """Test that detached signature verification in binary mode works."""
 
         key = self.generate_key("Adi Shamir", "rsa.com")
         datafn = os.path.join(_files, 'cypherpunk_manifesto')
@@ -715,7 +716,6 @@ class GPGTestCase(unittest.TestCase):
 
         datafd = open(datafn, 'rb')
         data = datafd.read()
-        datafd.close()
 
         sig = self.gpg.sign(data, default_key=key.fingerprint,
                             passphrase='adishamir',
@@ -734,11 +734,13 @@ class GPGTestCase(unittest.TestCase):
         with self.assertRaises(UnicodeDecodeError):
             print("SIG=%s" % sig)
 
-        verifysig = open(sigfn, 'rb')
-        verification = self.gpg.verify_file(data, verifysig)
+        datafd.seek(0)
+        verification = self.gpg.verify_file(datafd, sig_file=sigfn)
 
         self.assertTrue(isinstance(verification, gnupg._parsers.Verify))
-        self.assertFalse(verification.valid)
+        self.assertTrue(verification.valid)
+
+        datafd.close()
 
         if os.path.isfile(sigfn):
             os.unlink(sigfn)