diff --git a/gnupg.py b/gnupg.py
index f74f998..298ca57 100644
--- a/gnupg.py
+++ b/gnupg.py
@@ -649,25 +649,6 @@ def _threaded_copy_data(instream, outstream):
     wr.start()
     return wr
 
-def _underscore(input, remove_prefix=False):
-    """
-    Change hyphens to underscores so that GPG option names can be easily
-    tranlated to object attributes.
-
-    :type input: C{str}
-    :param input: The input intended for the gnupg process.
-
-    :type remove_prefix: C{bool}
-    :param remove_prefix: If True, strip leading hyphens from the input.
-
-    :rtype: C{str}
-    :return: The :param:input with hyphens changed to underscores.
-    """
-    if not remove_prefix:
-        return input.replace('-', '_')
-    else:
-        return input.lstrip('-').replace('-', '_')
-
 def _which(executable, flags=os.X_OK):
     """Borrowed from Twisted's :mod:twisted.python.proutils .