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Re: One-line password generator

From "Thomas Schmitt" <scdbackup@gmx.net>
Newsgroups linux.debian.user
Subject Re: One-line password generator
Date 2017-08-29 09:10 +0200
Message-ID <ujIOS-7YQ-15@gated-at.bofh.it> (permalink)
References <ujEBz-5eu-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hi,

Zenaan Harkness wrote:
> AIUI /dev/random is simply the input feed to /dev/urandom [...]

This is what the article by Thomas Huehn 
  https://www.2uo.de/myths-about-urandom/
calls a myth, illustrated by diagram
  https://www.2uo.de/myths-about-urandom/structure-no.png

Andy Smith stated in
  https://lists.debian.org/debian-user/2017/08/msg01594.html
that the article is correct.


> if you want security/ secure software, you -must- know the nature of
> your inputs,

I thought that i knew from the man page. But people with probably more
knowledge than me contradict that page.


I wrote:
> > I understand that in this situation there is no difference
> > between /dev/random and /dev/urandom.

> No

So this diagram about the situation before kernel 4.8 is wrong ?
  https://www.2uo.de/myths-about-urandom/structure-yes.png

The new situation as stated in
  https://www.2uo.de/myths-about-urandom/structure-new.png
is a bit more obscure, because it is not clear what exactly happens inside
the "randomness pool". Is it only a buffer ? Does it always grow when new
data arrive ? Or does it merge the new bits into a constant size pool ?


> > The difference appears only when the assumption of wealth is not
> > fulfilled.

> ... parse fail

"Wealth" = Well filled randomness pool which makes blocking unnessessary.


> don't use /dev/random, use /dev/urandom instead, as designed,

Urm. Your argumentation up to this point was that they differ sigificantly.

> and as has been made publicly clear for ~10 years now.

The kernel people won't get us users to change our behavior unless the
man page gets clarified and the experts take the responsibility to teach us
what https://www.2uo.de/myths-about-urandom/ tries to teach us.

The current statements look like a lame compromise after some of the
participating experts objected the flat deprecation of /dev/random
even after the system had a few seconds of collecting erratic events.

But what are these objections and why are they important enough to
cause a statement like
  "Choice of random source
   Unless you are doing long-term key generation (and most likely not
   even then), you probably shouldn't be reading from the /dev/random [...]"
in
  http://man7.org/linux/man-pages/man7/random.7.html

The clause "most likely not" puts the whole statement in question without
giving a clue about the proper answer.
Further it implies a vague security difference between both devices.


>   Confront the man page!

If only this would give more clarity ... X-|


My current compilation of all info is like this:

/dev/random was originally designed to possibly block, but is now said
not to do this any more in practice.
/dev/urandom was originally designed to hand out lower quality random
if /dev/random would block, but is now said not to do this any more.


Have a nice day :)

Thomas

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Thread

One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-22 17:10 +0200
  Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-22 21:50 +0200
    Re: One-line password generator <tomas@tuxteam.de> - 2017-08-22 22:10 +0200
      Re: One-line password generator John Hasler <jhasler@newsguy.com> - 2017-08-22 22:50 +0200
        Re: One-line password generator Jude DaShiell <jdashiel@panix.com> - 2017-08-23 14:40 +0200
    Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-22 22:20 +0200
      Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-22 22:20 +0200
      Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-22 22:30 +0200
        Re: One-line password generator Glenn English <ghe2001@gmail.com> - 2017-08-23 22:40 +0200
      Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-23 00:40 +0200
        Re: One-line password generator Lck Ras <likcoras@riseup.net> - 2017-08-23 02:30 +0200
          Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-23 19:20 +0200
            Re: One-line password generator Lck Ras <likcoras@riseup.net> - 2017-08-24 03:00 +0200
        Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-23 17:20 +0200
          Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-23 19:00 +0200
            Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-23 20:00 +0200
              Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-23 21:20 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-24 01:10 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-24 19:50 +0200
                Re: One-line password generator David Wright <deblis@lionunicorn.co.uk> - 2017-08-25 03:00 +0200
                Re: One-line password generator Curt <curty@free.fr> - 2017-08-25 10:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-25 11:30 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 15:40 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-25 16:50 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 18:10 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-25 19:20 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 20:10 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-25 20:50 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 21:00 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-25 19:00 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 19:00 +0200
                Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-25 19:20 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-25 20:20 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-25 19:20 +0200
    Re: One-line password generator Jape Person <japers@comcast.net> - 2017-08-22 22:20 +0200
      Re: One-line password generator Jude DaShiell <jdashiel@panix.com> - 2017-08-23 14:40 +0200
    Re: One-line password generator Mike McClain <mike.junk.46@att.net> - 2017-08-23 03:10 +0200
  Re: One-line password generator Teemu Likonen <tlikonen@iki.fi> - 2017-08-23 06:10 +0200
  Re: One-line password generator Aaron Toponce <aaron.toponce@gmail.com> - 2017-08-23 21:20 +0200
    Re: One-line password generator Greg Wooledge <wooledg@eeg.ccf.org> - 2017-08-23 21:30 +0200
      Re: One-line password generator Aaron Toponce <aaron.toponce@gmail.com> - 2017-08-23 21:40 +0200
        Re: One-line password generator Fungi4All <fungilife@protonmail.com> - 2017-08-23 22:50 +0200
          Re: One-line password generator Terence <terence.john@gmail.com> - 2017-08-23 23:40 +0200
  Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-26 20:30 +0200
    Re: One-line password generator Nicolas George <george@nsup.org> - 2017-08-26 20:40 +0200
      Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-26 21:10 +0200
        Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-27 16:00 +0200
    Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-26 21:20 +0200
      Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-27 16:00 +0200
        Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-27 17:10 +0200
          Re: One-line password generator Curt <curty@free.fr> - 2017-08-27 20:10 +0200
          Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-27 20:10 +0200
            Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-27 21:10 +0200
              Re: One-line password generator Andy Smith <andy@strugglers.net> - 2017-08-28 00:00 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-28 09:40 +0200
                Re: One-line password generator Curt <curty@free.fr> - 2017-08-28 11:40 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-28 12:10 +0200
                Re: One-line password generator Andy Smith <andy@strugglers.net> - 2017-08-28 13:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-28 15:20 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-29 04:40 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-29 09:10 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-29 10:50 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-29 11:00 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-29 12:50 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-29 13:00 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-29 14:30 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-30 03:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 12:40 +0200
                Re: One-line password generator Andy Smith <andy@strugglers.net> - 2017-08-29 14:10 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-29 15:00 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-30 03:50 +0200
                Re: One-line password generator Greg Wooledge <wooledg@eeg.ccf.org> - 2017-08-30 14:20 +0200
                Re: One-line password generator Gene Heskett <gheskett@shentel.net> - 2017-08-30 14:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 15:20 +0200
                Re: One-line password generator Gene Heskett <gheskett@shentel.net> - 2017-08-30 15:30 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 15:50 +0200
                Re: One-line password generator Gene Heskett <gheskett@shentel.net> - 2017-08-30 16:00 +0200
                Re: One-line password generator Greg Wooledge <wooledg@eeg.ccf.org> - 2017-08-30 16:10 +0200
                Re: One-line password generator Gene Heskett <gheskett@shentel.net> - 2017-08-30 18:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 16:30 +0200
                Re: One-line password generator Gene Heskett <gheskett@shentel.net> - 2017-08-30 20:10 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 23:00 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-01 10:40 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-01 10:50 +0200
                Re: One-line password generator Curt <curty@free.fr> - 2017-08-30 16:30 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 17:00 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-30 20:00 +0200
                Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-08-29 11:00 +0200
            Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-27 21:20 +0200
              Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-29 21:20 +0200
                Re: One-line password generator Reco <recoverym4n@gmail.com> - 2017-08-29 21:40 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-29 22:00 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-29 23:00 +0200
                Re: One-line password generator Curt <curty@free.fr> - 2017-08-30 10:50 +0200
                Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-08-30 12:40 +0200
                Re: One-line password generator Reco <recoverym4n@gmail.com> - 2017-08-30 00:00 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-31 21:10 +0200
                Re: One-line password generator Fungi4All <fungilife@protonmail.com> - 2017-08-31 21:20 +0200
                Re: One-line password generator Reco <recoverym4n@gmail.com> - 2017-08-31 21:40 +0200
    Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-27 04:20 +0200
      Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-08-27 16:00 +0200
        Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-27 16:40 +0200
  Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-09-01 17:00 +0200
    Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-09-01 21:50 +0200
      Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-01 23:50 +0200
        Re: One-line password generator Jude DaShiell <jdashiel@panix.com> - 2017-09-02 11:50 +0200
          Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-02 13:00 +0200
            Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-09-02 19:20 +0200
              Re: One-line password generator Jude DaShiell <jdashiel@panix.com> - 2017-09-02 20:30 +0200
              Re: One-line password generator "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-02 21:00 +0200
                Re: One-line password generator Brian <ad44@cityscape.co.uk> - 2017-09-02 22:00 +0200
      Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-09-02 01:50 +0200
    Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-09-02 01:50 +0200
      Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-09-02 04:40 +0200
        Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-09-02 05:40 +0200
          Re: One-line password generator Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-09-02 16:40 +0200
            Re: One-line password generator Zenaan Harkness <zenaan@freedbms.net> - 2017-09-04 01:10 +0200

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