1 files changed, 33 insertions, 0 deletions
diff --git a/OpenSSL/_util.py b/OpenSSL/_util.py
index 001a873..7c606b9 100644
--- a/OpenSSL/_util.py
+++ b/OpenSSL/_util.py
@@ -1,3 +1,5 @@
+from six import PY3, binary_type, text_type
+
 from cryptography.hazmat.bindings.openssl.binding import Binding
 binding = Binding()
 ffi = binding.ffi
@@ -15,3 +17,34 @@ def exception_from_error_queue(exceptionType):
                 ffi.string(lib.ERR_reason_error_string(error))))
 
     raise exceptionType(errors)
+
+
+
+def native(s):
+    """
+    Convert :py:class:`bytes` or :py:class:`unicode` to the native
+    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.
+
+    :raise UnicodeError: The input string is not UTF-8 decodeable.
+
+    :raise TypeError: The input is neither :py:class:`bytes` nor
+        :py:class:`unicode`.
+    """
+    if not isinstance(s, (binary_type, text_type)):
+        raise TypeError("%r is neither bytes nor unicode" % s)
+    if PY3:
+        if isinstance(s, binary_type):
+            return s.decode("utf-8")
+    else:
+        if isinstance(s, text_type):
+            return s.encode("utf-8")
+    return s
+
+
+
+if PY3:
+    def byte_string(s):
+        return s.encode("charmap")
+else:
+    def byte_string(s):
+        return s