[Python-Dev] Python 3.6 dict becomes compact and gets a private version; and keywords become ordered (original) (raw)

Gregory P. Smith greg at krypto.org
Mon Sep 12 18:59:47 EDT 2016

On Mon, Sep 12, 2016 at 3:57 PM Brett Cannon <brett at python.org> wrote:

On Mon, 12 Sep 2016 at 15:46 Ethan Furman <ethan at stoneleaf.us> wrote:

On 09/12/2016 09:27 AM, Gregory P. Smith wrote: > For the regular dict (non kwargs or namespace dict) use case I would actually like to /see disorder preserved during iteration/. > > If we don't, we will eventually to find ourselves in a similar state we were in pre hash-randomization: Does anyone have a short explanation of the interaction between hash randomization and this new always ordered dict? Why doesn't one make the other useless?

There is still a hash table that stores a pointer into an array that stores the keys/values that are kept in an ordered array. So that first-level hash table still uses hash randomization.

More specifically: If the goal of hash randomization is to reduce DDOS hash table stuffing attacks, that is still true. The hashing is randomized.

Dict ordering may actually help DDOS protection. It no longer leaks information potentially revealing details about the hash seed via the iteration order.

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