Re: Hello World

References	<54957226$0$12975$c3e8da3$5496439d@news.astraweb.com> <54971df7$0$30820$b1db1813$ba2d9d20@news.astraweb.com> <54974ed7$0$12986$c3e8da3$5496439d@news.astraweb.com> <roy-2DE8D9.18502021122014@news.panix.com> <m79ghk$o5r$3@reader1.panix.com>
Date	2014-12-23 04:25 +1100
Subject	Re: Hello World
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.17128.1419269130.18130.python-list@python.org> (permalink)

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On Tue, Dec 23, 2014 at 3:23 AM, Grant Edwards <invalid@invalid.invalid> wrote:
>> Heh.  I once worked on a C++ project that included its own crypo code
>> (i.e. custom implementations of things like AES and SHA-1).
>
> Damn.  Should I ever start to do something like that (for a real
> product), I hereby officially request that somebody please try to slap
> some sense into me.

Likewise. And I'll happily do the slapping.

There's one exception. Writing your own crypto is a bad idea if that
means reimplementing AES... but if you want something that's effective
on completely different levels, sometimes it's best to write your own.
I had a project a while ago that needed some encryption work done, and
I implemented something that I described as "scarily effective". My
boss demanded that the debug code-execution feature be protected by a
password that would be strong even if someone could read the source
code, so I put together something that would hash the incoming
password, then check to see if the first two and last two bytes of the
hash were all the same byte value as the current hour-of-week (ranging
from 0 to 167). This is clearly more secure than simply embedding a
SHA256 hash in the source code, because you can't possibly
reverse-engineer it (since you don't even have the full hash). And
yes, this was 100% effective in convincing my boss that the code
executor was safely guarded. Since that was the goal, having several
lines of complex and opaque code was far better than a single line
that says "if hash(password)=='5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8':
do stuff", which is way too easy for someone to decode.

And it was, indeed, scarily effective. That lasted for a long time,
and any time there was a question about security, I could just point
to that and say "See? Safe."...

ChrisA

Thread

Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-20 23:57 +1100
  Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-21 00:11 +1100
  Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-20 16:13 +0000
  Re: Hello World Rustom Mody <rustompmody@gmail.com> - 2014-12-20 08:50 -0800
  Re: Hello World Steve Hayes <hayesstw@telkomsa.net> - 2014-12-20 20:39 +0200
  Re: Hello World alister <alister.nospam.ware@ntlworld.com> - 2014-12-20 22:18 +0000
  Re: Hello World CM <cmpython@gmail.com> - 2014-12-20 21:14 -0800
    Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-21 16:26 +1100
    Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-21 16:31 +1100
    Re: Hello World Terry Reedy <tjreedy@udel.edu> - 2014-12-21 01:31 -0500
      Re: Hello World wxjmfauth@gmail.com - 2014-12-21 00:07 -0800
    Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-21 17:44 +1100
      Re: Hello World CM <cmpython@gmail.com> - 2014-12-20 23:44 -0800
        Re: Hello World CM <cmpython@gmail.com> - 2014-12-20 23:45 -0800
          Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2014-12-21 10:26 +0200
        Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-21 18:46 +1100
      Re: Hello World albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-08 12:43 +0000
        Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-08 23:53 +1100
          Re: Hello World albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-08 13:37 +0000
          Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2015-01-08 16:06 +0200
            Re: Hello World alister <alister.nospam.ware@ntlworld.com> - 2015-01-08 14:21 +0000
              Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2015-01-08 16:31 +0200
                Re: Hello World alister <alister.nospam.ware@ntlworld.com> - 2015-01-08 15:14 +0000
          Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-08 15:11 +0100
          Re: Hello World albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-17 14:51 +0000
            Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 01:57 +1100
              Re: Hello World cl@isbd.net - 2015-01-17 15:18 +0000
            Re: Hello World Michael Torrie <torriem@gmail.com> - 2015-01-17 09:29 -0700
              Re: Hello World cl@isbd.net - 2015-01-17 16:47 +0000
                Re: Hello World albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-17 18:06 +0000
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-17 19:47 +0100
                Re: Hello World Michael Torrie <torriem@gmail.com> - 2015-01-17 19:09 -0700
                Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-01-18 13:37 +1100
                Re: Hello World Roy Smith <roy@panix.com> - 2015-01-17 22:18 -0500
                Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-01-18 14:45 +1100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 18:45 +1100
                Re: Hello World Roy Smith <roy@panix.com> - 2015-01-18 07:26 -0500
                Re: Hello World Tim Chase <python.list@tim.thechases.com> - 2015-01-17 21:50 -0600
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 18:44 +1100
                Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-01-17 18:31 +0000
                Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-01-18 10:46 +1100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 11:04 +1100
                Re: Hello World Jason Friedman <jsf80238@gmail.com> - 2015-01-17 18:19 -0700
                Re: Hello World Michael Torrie <torriem@gmail.com> - 2015-01-17 19:13 -0700
                Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2015-01-18 12:03 +0200
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 14:34 +0100
                Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2015-01-18 18:03 +0200
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 19:39 +0100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 21:10 +1100
                Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2015-01-18 22:50 +0200
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 14:32 +0100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-18 21:00 +1100
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 14:35 +0100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-19 00:57 +1100
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 16:48 +0100
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-19 04:08 +1100
                Re: Hello World Michael Ströder <michael@stroeder.com> - 2015-01-18 14:30 +0100
        Re: Hello World Steve Hayes <hayesstw@telkomsa.net> - 2015-01-08 19:02 +0200
          Re: Hello World Chris Angelico <rosuav@gmail.com> - 2015-01-09 04:11 +1100
            Re: Hello World albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-17 15:10 +0000
          Re: Hello World Michael Torrie <torriem@gmail.com> - 2015-01-08 10:53 -0700
            Re: Hello World Grant Edwards <invalid@invalid.invalid> - 2015-01-08 18:57 +0000
    Re: Hello World Devin Jeanpierre <jeanpierreda@gmail.com> - 2015-01-17 16:06 -0800
  Re: Hello World Tony the Tiger <tony@tiger.invalid> - 2014-12-21 19:22 +0000
    Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2014-12-21 22:02 +0200
    Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-22 09:51 +1100
      Re: Hello World Roy Smith <roy@panix.com> - 2014-12-21 18:50 -0500
        Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-22 11:10 +1100
          Re: Hello World Roy Smith <roy@panix.com> - 2014-12-21 19:12 -0500
            Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-22 11:36 +1100
          Re: Hello World mm0fmf <none@mailinator.com> - 2014-12-22 00:20 +0000
            Re: Hello World Tim Chase <python.list@tim.thechases.com> - 2014-12-21 18:47 -0600
            Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-22 02:56 +0000
          Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2014-12-22 10:52 +0200
            Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-22 20:01 +1100
        Re: Hello World Grant Edwards <invalid@invalid.invalid> - 2014-12-22 16:23 +0000
          Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-23 04:25 +1100
          Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-22 18:51 +0000
          Re: Hello World MRAB <python@mrabarnett.plus.com> - 2014-12-22 19:05 +0000
          Re: Hello World Tim Chase <python.list@tim.thechases.com> - 2014-12-22 13:16 -0600
            Re: Hello World Roy Smith <roy@panix.com> - 2014-12-22 19:55 -0500
              Re: Hello World sohcahtoa82@gmail.com - 2014-12-22 17:03 -0800
                Re: Hello World MRAB <python@mrabarnett.plus.com> - 2014-12-23 01:37 +0000
                Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-23 12:39 +1100
                Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-23 02:36 +0000
                Re: Hello World Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-12-23 12:24 -0500
              Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-23 12:03 +1100
          Encryption - was Hello World Dave Angel <d@davea.name> - 2014-12-22 14:57 -0500
          Re: Encryption - was Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-23 09:29 +1100
          Re: Encryption - was Hello World Dave Angel <davea@davea.name> - 2014-12-22 18:22 -0500
      Re: Hello World Rustom Mody <rustompmody@gmail.com> - 2014-12-21 18:37 -0800
      Re: Hello World Steve Hayes <hayesstw@telkomsa.net> - 2014-12-22 08:21 +0200
        Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-22 17:33 +1100
          Re: Hello World Steve Hayes <hayesstw@telkomsa.net> - 2014-12-22 09:46 +0200
            Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-22 18:56 +1100
        Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-22 20:18 +1100
          Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2014-12-22 11:34 +0200
            Re: Hello World Rustom Mody <rustompmody@gmail.com> - 2014-12-22 19:38 -0800
          Re: Hello World Roy Smith <roy@panix.com> - 2014-12-22 08:15 -0500
            Re: Hello World Chris Angelico <rosuav@gmail.com> - 2014-12-23 00:23 +1100
              OFF TOPIC Snow Crash [was Re: Hello World] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-23 13:09 +1100
                Re: OFF TOPIC Snow Crash [was Re: Hello World] Grant Edwards <invalid@invalid.invalid> - 2014-12-23 16:20 +0000
                Re: OFF TOPIC Snow Crash [was Re: Hello World] Rustom Mody <rustompmody@gmail.com> - 2014-12-23 08:41 -0800
                Re: OFF TOPIC Snow Crash [was Re: Hello World] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-24 12:51 +1100
                Re: OFF TOPIC Snow Crash [was Re: Hello World] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-24 14:18 +1100
                Re: OFF TOPIC Snow Crash [was Re: Hello World] alister <alister.nospam.ware@ntlworld.com> - 2014-12-24 11:50 +0000
                Re: OFF TOPIC Snow Crash [was Re: Hello World] alex23 <wuwei23@gmail.com> - 2014-12-26 09:34 +1000
                Re: OFF TOPIC Snow Crash [was Re: Hello World] alex23 <wuwei23@gmail.com> - 2014-12-26 09:27 +1000
                Re: OFF TOPIC Snow Crash [was Re: Hello World] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-26 15:13 +1100
                Re: OFF TOPIC Snow Crash [was Re: Hello World] alister <alister.nospam.ware@ntlworld.com> - 2014-12-26 10:03 +0000
            Re: Hello World Marko Rauhamaa <marko@pacujo.net> - 2014-12-22 15:26 +0200
              Re: Hello World Roy Smith <roy@panix.com> - 2014-12-22 08:41 -0500
        Re: Hello World Roy Smith <roy@panix.com> - 2014-12-22 08:13 -0500
          Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-23 02:22 +1100
            Re: Hello World Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-22 17:36 +0200
              Re: Hello World Chris Warrick <kwpolska@gmail.com> - 2014-12-22 17:03 +0100
            Re: Hello World Skip Montanaro <skip.montanaro@gmail.com> - 2014-12-22 09:39 -0600
              Re: Hello World Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-23 03:54 +1100
            Re: Hello World Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-22 18:48 +0000
        Re: Hello World Grant Edwards <invalid@invalid.invalid> - 2014-12-22 16:26 +0000
    Re: Hello World Grant Edwards <invalid@invalid.invalid> - 2014-12-22 16:18 +0000
      Re: Hello World alister <alister.nospam.ware@ntlworld.com> - 2014-12-22 19:05 +0000

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