- Issue #13703: oCERT-2011-003: add -R command-line option and PYTHONHASHSEED

environment variable, to provide an opt-in way to protect against denial of
  service attacks due to hash collisions within the dict and set types.  Patch
  by David Malcolm, based on work by Victor Stinner.

Lib/os.py

@@ -742,22 +742,3 @@ try:
                      _make_statvfs_result)
 except NameError: # statvfs_result may not exist
     pass
-
-if not _exists("urandom"):
-    def urandom(n):
-        """urandom(n) -> str
-
-        Return a string of n random bytes suitable for cryptographic use.
-
-        """
-        try:
-            _urandomfd = open("/dev/urandom", O_RDONLY)
-        except (OSError, IOError):
-            raise NotImplementedError("/dev/urandom (or equivalent) not found")
-        try:
-            bs = b""
-            while n - len(bs) >= 1:
-                bs += read(_urandomfd, n - len(bs))
-        finally:
-            close(_urandomfd)
-        return bs