enable hash randomization by default
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 85953ad..3fb0bf6 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1277,7 +1277,29 @@
inheritance of :meth:`__hash__` will be blocked, just as if :attr:`__hash__`
had been explicitly set to :const:`None`.
- See also the :option:`-R` command-line option.
+
+ .. note::
+
+ Note by default the :meth:`__hash__` values of str, bytes and datetime
+ objects are "salted" with an unpredictable random value. Although they
+ remain constant within an individual Python process, they are not
+ predictable between repeated invocations of Python.
+
+ This is intended to provide protection against a denial-of-service caused
+ by carefully-chosen inputs that exploit the worst case performance of a
+ dict insertion, O(n^2) complexity. See
+ http://www.ocert.org/advisories/ocert-2011-003.html for details.
+
+ Changing hash values affects the order in which keys are retrieved from a
+ dict. Although Python has never made guarantees about this ordering (and
+ it typically varies between 32-bit and 64-bit builds), enough real-world
+ code implicitly relies on this non-guaranteed behavior that the
+ randomization is disabled by default.
+
+ See also :envvar:`PYTHONHASHSEED`.
+
+ .. versionchanged:: 3.3
+ Hash randomization is enabled by default.
.. method:: object.__bool__(self)
diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
index b97dbcd..64d453e 100644
--- a/Doc/using/cmdline.rst
+++ b/Doc/using/cmdline.rst
@@ -24,7 +24,7 @@
When invoking Python, you may specify any of these options::
- python [-bBdEhiORqsSuvVWx?] [-c command | -m module-name | script | - ] [args]
+ python [-bBdEhiOqsSuvVWx?] [-c command | -m module-name | script | - ] [args]
The most common use case is, of course, a simple invocation of a script::
@@ -486,9 +486,8 @@
.. envvar:: PYTHONHASHSEED
- If this variable is set to ``random``, the effect is the same as specifying
- the :option:`-R` option: a random value is used to seed the hashes of str,
- bytes and datetime objects.
+ If this variable is set to ``random``, a random value is used to seed the
+ hashes of str, bytes and datetime objects.
If :envvar:`PYTHONHASHSEED` is set to an integer value, it is used as a fixed
seed for generating the hash() of the types covered by the hash
@@ -499,8 +498,7 @@
values.
The integer must be a decimal number in the range [0,4294967295]. Specifying
- the value 0 will lead to the same hash values as when hash randomization is
- disabled.
+ the value 0 will disable hash randomization.
.. versionadded:: 3.2.3