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From: Jean Louis <bugs@gnu.support>
To: Yuri Khan <yuri.v.khan@gmail.com>
Cc: help-gnu-emacs <help-gnu-emacs@gnu.org>
Subject: About randomity, entropy, random passwords - was Re: Noob dumb question (extending emacs)
Date: Mon, 25 Oct 2021 23:29:43 +0300	[thread overview]
Message-ID: <YXcTt2EVcq1QDy7+@protected.localdomain> (raw)
In-Reply-To: <CAP_d_8WWJOa-ApaNfUm5BeOCN-fC7=eiZb+VM6VYHMoR9eb6dQ@mail.gmail.com>

* Yuri Khan <yuri.v.khan@gmail.com> [2021-10-25 23:12]:
> On Tue, 26 Oct 2021 at 02:25, Jean Louis <bugs@gnu.support> wrote:
> 
> > Yuri and Michael H., you are very right, too simple password
> > generation without enough entropy produces duplicate passwords.
> 
> What tipped you to this conclusion?

I did the `dotimes' and found same passwords without goods seed. Then
I have improved the seed.

> Still wrong!

You still cannot guess the next password coming... with or without
good seed. But your tips did make it more random on my side. ;-p

> > (defun rcd-read-urandom (&optional length)
> >   "I am also free to modify the Emacs Lisp unlimited times."
> >   (shell-command-to-string "head -n 1 /dev/urandom"))
> 
> Here you read the first newline-delimited line of /dev/urandom, which
> may be a lot. If you have to use ‘head’, use it with -c and give a
> byte count.

That one I forgot the same time I wrote it, it was just thinking. I
don't like external commands.

> > (defun rcd-password-generate-1 (string)
> >   "Return capitalized or downcased single symbol from a string"
> >   (random (format "%s" (rcd-read-urandom)))
> 
> Here you seed the Emacs random generator with the entropy. However,
> the Emacs random generator can only use 48 bits of entropy in the best
> case, so it grabs exactly that and drops the remainder on the floor.

It may be, I dropped that one.

> >   (let* ((max (length string))
> >          (rnd (random max))
> >          (single (substring string rnd (+ rnd 1))))
> >     single))
> 
> Then you proceed to generate a random password using the seeded
> pseudo-random generator. Which is a step up from an unseeded
> pseudo-random generator (you could generate a series of passwords from
> a single seed, making it easier for the attacker who knows one to
> guess others) but still not as random as you would get by just
> converting raw entropy into printable characters.

I'll stick to random Emacs uptime concatenated to microseconds,
nanoseconds and milliseconds.


-- 
Jean

Take action in Free Software Foundation campaigns:
https://www.fsf.org/campaigns

In support of Richard M. Stallman
https://stallmansupport.org/



  parent reply	other threads:[~2021-10-25 20:29 UTC|newest]

Thread overview: 127+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-19 22:12 Noob dumb question (extending emacs) Ivano Da Milano
2021-10-20  0:36 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-20  6:34   ` Marcin Borkowski
2021-10-20 18:13     ` H. Dieter Wilhelm
2021-10-20  6:53   ` Jean Louis
2021-10-20  8:23     ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-20 17:10   ` Ivano Da Milano
2021-10-20 18:41     ` Tassilo Horn
2021-10-20 18:56     ` Ken Goldman
2021-10-20 19:01       ` Ivano Da Milano
2021-10-20 19:45     ` Jean Louis
2021-10-21  5:27       ` Ivano Da Milano
2021-10-21  7:40         ` H. Dieter Wilhelm
2021-10-21 15:46           ` Ivano Da Milano
2021-10-21 16:03             ` H. Dieter Wilhelm
2021-10-21 17:49               ` Ivano Da Milano
2021-10-21 18:51         ` Jean Louis
2021-10-21 20:02           ` H. Dieter Wilhelm
2021-10-21 22:58             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22  6:59               ` H. Dieter Wilhelm
2021-10-22 12:18                 ` Jean Louis
2021-10-22 12:56                   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22 13:14                     ` Yuri Khan
2021-10-22 17:51                       ` Jean Louis
2021-10-22 18:50                         ` Yuri Khan
2021-10-22 19:29                           ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22 21:22                           ` Jean Louis
2021-10-23 18:08                             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  7:10                               ` Jean Louis
2021-10-24  9:35                                 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24 17:41                                   ` Jean Louis
2021-10-24 18:20                                     ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25  5:47                                       ` Jean Louis
2021-10-25  9:40                                         ` Yuri Khan
2021-10-25 10:23                                           ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 12:41                                           ` Jean Louis
2021-10-25 19:22                                           ` Jean Louis
2021-10-25 19:46                                             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 19:52                                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 19:56                                                 ` About randomity, entropy, random passwords - was " Jean Louis
2021-10-25 20:29                                                   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 20:00                                               ` Jean Louis
2021-10-25 19:56                                             ` Yuri Khan
2021-10-25 20:24                                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 20:34                                                 ` Jean Louis
2021-10-25 20:29                                               ` Jean Louis [this message]
2021-10-28 20:39                                         ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-23  8:41                           ` Michael Heerdegen
2021-10-23 10:16                             ` Yuri Khan
2021-10-23 10:46                               ` Michael Heerdegen
2021-10-23 18:27                                 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  8:16                                   ` Michael Heerdegen
2021-10-28  2:24                                     ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-28 11:41                                       ` Michael Heerdegen
2021-10-28 12:07                                         ` tomas
2021-10-28 20:56                                         ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-28 22:54                                           ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-31 20:46                                             ` Michael Heerdegen
2021-11-01  2:09                                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-11-01 19:38                                                 ` Michael Heerdegen
2021-11-03  1:06                                                   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-11-03 21:24                                                     ` Michael Heerdegen
2021-11-03 22:16                                                       ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-11-05 19:03                                                 ` Jean Louis
2021-11-05 21:50                                                   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-31 20:42                                           ` Michael Heerdegen
2021-11-05 18:59                                       ` Jean Louis
2021-10-23 12:54                               ` Michael Heerdegen
2021-10-23 13:07                                 ` Yuri Khan
2021-10-23 18:41                                   ` ERC links to man pages (was: Re: Noob dumb question (extending emacs)) Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  7:08                                   ` Noob dumb question (extending emacs) Jean Louis
2021-10-24  8:57                                     ` Michael Heerdegen
2021-10-24 17:59                                       ` Jean Louis
2021-10-25  9:18                                         ` Michael Heerdegen
2021-10-25  9:33                                           ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 19:44                                             ` Jean Louis
2021-10-25 20:20                                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25 20:33                                                 ` Jean Louis
2021-10-25 12:45                                           ` Jean Louis
2021-10-25 13:20                                             ` Michael Heerdegen
2021-10-25 19:54                                               ` About randomity, entropy, random passwords - was " Jean Louis
     [not found]                                               ` <YXcLIC+doASdNFll@protected.localdomain>
     [not found]                                                 ` <87cznryfnz.fsf@web.de>
2021-10-26 18:52                                                   ` Jean Louis
2021-10-23 18:22                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-23 19:52                                 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  6:43                               ` Jean Louis
2021-10-24  8:28                                 ` Michael Heerdegen
2021-10-24 18:03                                   ` Jean Louis
2021-10-24  9:31                                 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24 18:09                                   ` Jean Louis
2021-10-24 18:30                                     ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25  5:31                                       ` Jean Louis
2021-10-28  2:33                                         ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-11-05 19:09                                           ` Passwords -- " Jean Louis
2021-11-05 22:00                                             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-23 18:17                             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  8:42                               ` Michael Heerdegen
2021-10-22 18:55                         ` Yuri Khan
2021-10-22 19:30                           ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22 21:31                           ` Jean Louis
2021-10-22 22:21                             ` H. Dieter Wilhelm
2021-10-23 10:46                             ` Yuri Khan
2021-10-23 18:13                               ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  7:48                                 ` Yuri Khan
2021-10-24  9:37                                   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-24  6:45                               ` Jean Louis
2021-10-24  8:50                                 ` Michael Heerdegen
2021-10-24 17:20                                   ` Jean Louis
2021-10-24 18:17                                 ` Yuri Khan
2021-10-24 19:07                                   ` Jean Louis
2021-10-24 19:05                           ` Jean Louis
2021-10-25  0:12                             ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-25  3:54                               ` Jean Louis
2021-10-22 18:57                         ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22 18:53                       ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-22 17:48                     ` Jean Louis
2021-10-22 19:26                       ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-21 19:45     ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-20  4:04 ` Ivano Da Milano
2021-10-20  5:46 ` H. Dieter Wilhelm
2021-10-20  5:58   ` Emanuel Berg via Users list for the GNU Emacs text editor
     [not found]   ` <CAPWV0kyjr0=FrkVkH+Wf573fddX3pM4iiEfkQJ6oe1J_pQuNPA@mail.gmail.com>
     [not found]     ` <86a6j3wo7y.fsf@duenenhof-wilhelm.de>
     [not found]       ` <CAPWV0kyogB+u0X4dUhpyEox6pih1MJkjE2e_OoqQoP81NZceHQ@mail.gmail.com>
2021-10-20 18:31         ` Fwd: " Ivano Da Milano
2021-10-20  6:50 ` Jean Louis
2021-10-20  8:20   ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-20 14:13     ` Jean Louis
2021-10-21 19:56       ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-10-23 10:51         ` Tassilo Horn
2021-10-23 18:36           ` Emanuel Berg via Users list for the GNU Emacs text editor

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