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Groups > comp.lang.c++ > #87041
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: CHAR_BIT is not eight |
| Date | 2022-10-17 10:09 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <tij2k2$3daer$1@dont-email.me> (permalink) |
| References | (11 earlier) <tie65c$2n1ei$1@dont-email.me> <efe1c230-2ee5-48da-ad7c-88a3d8bcbe1en@googlegroups.com> <tif3rh$2t8mc$2@dont-email.me> <80d4f942-0740-455e-96e7-c21fd561291fn@googlegroups.com> <tihphj$37j3o$2@dont-email.me> |
On 16/10/2022 22:28, Vir Campestris wrote: > On 15/10/2022 23:42, Frederick Virchanza Gotham wrote: >> On Saturday, October 15, 2022 at 9:06:25 PM UTC+1, Chris M. Thomasson >> wrote: >> >>> Did you actually write the cipher? Or did you get the code from GitHub? >> >> >> I can't find an algorithm that will fit on the microcontroller so I'm >> writing my own. >> 99% of the program memory is already taken up. > > I too have been in the position where every byte counts. Abbreviating > error messages was usually the easiest fix. > > But... > > I've also done a reasonable amount of cryptography. A home rolled > algorithm will usually have a hole in it somewhere. You'll get away with > it if the stuff you are protecting is obscure enough, and not worth a > lot, but I wouldn't trust my life or any serious amounts of money to it. > From his description, it sounds like the encryption does not have to cover more than a small code key. That reduces the risk somewhat - many attacks on encryption systems rely on sending specially crafted packets, or examining long encrypted streams where you can guess some of the original content (like html tags). For a short enough message, sent rarely, it's probably enough to xor the message bytes with the results of a pseudorandom generator. You don't need to re-implement OpenSSL for a 16 byte message. Still, it's a very good point you make - good encryption implementations are not always easy even if you have all the details of the algorithm. If the hardware is still in flux, an option is an external encryption chip. You can get small and cheap devices that are easy to integrate with such microcontrollers - Microchip (the manufacturers of the AVR in the Arduino) have them.
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CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-12 15:57 -0700
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-12 16:01 -0700
Re: CHAR_BIT is not eight Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-10-12 17:16 -0700
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-13 11:38 +0200
Re: CHAR_BIT is not eight Michael S <already5chosen@yahoo.com> - 2022-11-16 06:24 -0800
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-11-17 11:04 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-11-17 16:40 +0000
Re: CHAR_BIT is not eight Richard Damon <Richard@Damon-Family.org> - 2022-11-17 23:23 -0500
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-11-18 08:16 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-11-18 16:33 +0000
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-11-18 18:54 +0100
Re: CHAR_BIT is not eight Michael S <already5chosen@yahoo.com> - 2022-11-18 03:47 -0800
Re: CHAR_BIT is not eight scott@slp53.sl.home (Scott Lurndal) - 2022-11-18 14:52 +0000
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-11-18 16:32 +0000
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-11-18 19:05 +0100
Re: CHAR_BIT is not eight scott@slp53.sl.home (Scott Lurndal) - 2022-11-18 18:16 +0000
Re: CHAR_BIT is not eight Juha Nieminen <nospam@thanks.invalid> - 2022-10-13 08:02 +0000
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-13 08:08 +0000
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-15 11:35 +0200
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-15 02:53 -0700
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-15 11:57 +0200
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-15 03:05 -0700
Re: CHAR_BIT is not eight Juha Nieminen <nospam@thanks.invalid> - 2022-10-17 06:18 +0000
Re: CHAR_BIT is not eight Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-17 15:29 -0500
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-13 02:06 -0700
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-13 11:42 +0200
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-13 15:36 +0000
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-13 23:06 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-13 22:30 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-14 15:27 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-14 14:47 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-14 14:58 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-14 21:01 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-15 10:28 +0000
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-15 13:39 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 12:45 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-15 15:18 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 16:24 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-15 15:34 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 16:39 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-15 15:53 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 16:55 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-15 15:57 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 16:59 +0100
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-17 15:27 +0000
Re: CHAR_BIT is not eight "daniel...@gmail.com" <danielaparker@gmail.com> - 2022-10-17 09:04 -0700
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-17 16:13 +0000
Re: CHAR_BIT is not eight red floyd <no.spam.here@its.invalid> - 2022-10-17 09:44 -0700
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-17 17:47 +0100
Re: CHAR_BIT is not eight Manfred <noname@add.invalid> - 2022-10-18 01:10 +0200
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-17 16:22 -0700
Re: CHAR_BIT is not eight Paul N <gw7rib@aol.com> - 2022-10-18 05:13 -0700
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-18 15:04 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-18 17:40 +0100
Re: CHAR_BIT is not eight "daniel...@gmail.com" <danielaparker@gmail.com> - 2022-10-18 12:14 -0700
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-19 15:12 +0000
Re: CHAR_BIT is not eight scott@slp53.sl.home (Scott Lurndal) - 2022-10-19 15:35 +0000
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-20 16:16 +0000
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-15 20:13 +0200
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-15 20:11 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-15 20:03 +0100
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-16 07:51 +0200
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-16 17:03 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-16 16:34 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-16 18:51 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-16 18:11 +0100
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-16 19:18 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-16 22:02 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-16 21:19 +0100
Re: CHAR_BIT is not eight scott@slp53.sl.home (Scott Lurndal) - 2022-10-16 21:24 +0000
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-16 14:38 -0700
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-16 14:48 -0700
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-16 22:39 +0100
Re: CHAR_BIT is not eight scott@slp53.sl.home (Scott Lurndal) - 2022-10-16 23:49 +0000
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-17 09:54 +0200
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-17 17:31 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-17 19:56 +0200
Re: CHAR_BIT is not eight Muttley@dastardlyhq.com - 2022-10-17 15:29 +0000
Re: CHAR_BIT is not eight Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-10-17 17:33 +0100
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-15 11:55 -0700
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-15 13:06 -0700
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-15 15:42 -0700
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-16 19:10 +0200
Re: CHAR_BIT is not eight Vir Campestris <vir.campestris@invalid.invalid> - 2022-10-16 21:28 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-17 10:09 +0200
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-16 13:35 -0700
Re: CHAR_BIT is not eight "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-16 13:36 -0700
Re: CHAR_BIT is not eight Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-11-02 17:46 -0700
Re: CHAR_BIT is not eight Bo Persson <bo@bo-persson.se> - 2022-10-13 11:10 +0200
Re: CHAR_BIT is not eight Juha Nieminen <nospam@thanks.invalid> - 2022-10-13 10:49 +0000
Re: CHAR_BIT is not eight Juha Nieminen <nospam@thanks.invalid> - 2022-10-13 12:05 +0000
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-13 06:34 -0700
Re: CHAR_BIT is not eight Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-13 15:24 +0100
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-13 15:59 +0200
Re: CHAR_BIT is not eight Juha Nieminen <nospam@thanks.invalid> - 2022-10-14 05:54 +0000
Re: CHAR_BIT is not eight Paavo Helde <eesnimi@osa.pri.ee> - 2022-10-14 09:16 +0300
Re: CHAR_BIT is not eight Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-11-16 05:41 -0800
Re: CHAR_BIT is not eight Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-11-16 10:38 -0800
Re: CHAR_BIT is not eight Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-05 11:42 -0800
Re: CHAR_BIT is not eight Öö Tiib <ootiib@hot.ee> - 2022-12-06 01:03 -0800
Re: CHAR_BIT is not eight Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-28 20:49 -0800
Re: CHAR_BIT is not eight Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-10-14 00:17 -0700
Re: CHAR_BIT is not eight David Brown <david.brown@hesbynett.no> - 2022-10-14 15:33 +0200
Re: CHAR_BIT is not eight Vir Campestris <vir.campestris@invalid.invalid> - 2022-10-16 21:37 +0100
Re: CHAR_BIT is not eight Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-17 15:24 -0500
Re: CHAR_BIT is not eight Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-15 11:34 +0200
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