Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:96000
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain ohgaki.net designates 180.42.98.130 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <87vaxyuz0n.fsf@lil.giraffy.jp>
References: <CAGa2bXYg1kkoYGQNr8T2oTshuqrvweefYO+EdY41w1vwUM32iQ@mail.gmail.com>
 <878tuxenl4.fsf@lil.giraffy.jp> <CAGa2bXaTydTSZniX4dUA9h_FcNaymyqfDXQJO0zx1ZDfLmvWdg@mail.gmail.com>
 <87twdlcs2j.fsf@lil.giraffy.jp> <CAGa2bXaziNMtNAgsJgX-BCgLL9z2WkoSaP8aNVrAgwo9MJ4WEQ@mail.gmail.com>
 <87h99lch13.fsf@lil.giraffy.jp> <CAGa2bXYeWZSx2vOYPhnCJ_O7ry2jPNNPcm=mpNuVJAwYAY5sMA@mail.gmail.com>
 <877fagczci.fsf@lil.giraffy.jp> <CAGa2bXZPrarOmRvYiDVar3qw1bUyHXsnMYRsgkPbvwXHO8BLuw@mail.gmail.com>
 <CAGa2bXYJ2=Tn20zy2BkXJCgAxuEq08Bv7ZA85GtYPZND3dTK2g@mail.gmail.com>
 <87mvjcbfcb.fsf@lil.giraffy.jp> <CAGa2bXa-nSDgJfyaGWLFkG3m637Q7S=G5NWO2Wu7eLJqLe3Zgg@mail.gmail.com>
 <877fagwc5o.fsf@lil.giraffy.jp> <CAGa2bXawn3Vv3gKfUdhd-M5RdJHW0XHyJatZ+D7dAhnTqhyang@mail.gmail.com>
 <87vaxyuz0n.fsf@lil.giraffy.jp>
Date: Thu, 15 Sep 2016 06:06:04 +0900
Message-ID: <CAGa2bXZeSq7UaWV6M1VUw0jowOCbaCzTbbW-0KWczqEG6fu_+g@mail.gmail.com>
To: Kazuo Oishi <kazuo@o-ishi.jp>
Cc: "internals@lists.php.net" <internals@lists.php.net>
Content-Type: text/plain; charset=UTF-8
Subject: Re: [PHP-DEV] [RFC][DISCUSSION] Improve uniqid() uniqueness
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

Hi Kazuo,

On Thu, Sep 15, 2016 at 3:17 AM, Kazuo Oishi <kazuo@o-ishi.jp> wrote:
>> I updated the RFC.
>> 2nd parameter (more_entropy) is int now.
>>
>>  - 0 for disable more entropy.
>>    (Compatible with current $more_entropy=FALSE)
>>  - 1 for 10 digits entropy. e.g. 1.23456789
>>    (Compatible with current $more_entropy=TRUE) DEFAULT
>>  - 13 to 255 to number of entropy [0-v]{13,255} chars.
>>    e.g. 1234abcdefghi (13 = 65 bits)
>>    65 bits entropy + timestamp will provide good enough uniqueness for
>> most usage.
>>
>> More secure default may be future scope, but attack against misused
>> code will be much harder by default as a bonus.
>>
>> Default could be more secure by using [0-v]+.
>> Marco does not like "." in default output.
>>
>> I would like to choose default from discussion (or make some vote choices)
>
> Basically, I will not oppose if backward compatibility is kept (default
> $number_of_entropy_chars = 0).  I have no opinion about specifying
> length of entropy chars.
>
> However, I don't think this new 2nd parameter design is good.
>
>  - It is not natural (or straightforward) to specify 1 as
>    parameter named $number_of_entropy_chars, to use 10 digits
>    entropy ($more_entropy=TRUE compatible output).
>
>  - Why number of new style entropy ([0-9a-v]+) starts with 13?
>    (Why not 2 or 11?)
>
>  - Why max number of entropy is 255? (32^255 = 1275 bits)
>    (Ease of implementation?)
>
> And, what will happen when 2-12, greater than 255, or negative
> value is specified?

I'm going to propose more compatible fix that does not change
length of entropy chars nor parameter type.
Anyway, I was thinking to raise error for any invalid numbers.

I'm going to propose

  A. Current format (digits and .   e.g. 1.23456788)
  B.  HEX format ([0-9a-f]{10})

I'll make these vote options.

A is compatible with  when $more_entropy=TRUE.
B uses compatible chars without $more_entropy (=FALSE).

Regards,

--
Yasuo Ohgaki
yohgaki@ohgaki.net