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Groups > comp.arch.embedded > #31810
| From | Stefan Reuther <stefan.news@arcor.de> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Embedding a Checksum in an Image File |
| Date | 2023-04-21 19:40 +0200 |
| Message-ID | <u1uoqs.17k.1@stefan.msgid.phost.de> (permalink) |
| References | <116ff07e-5e25-469a-90a0-9474108aadd3n@googlegroups.com> <pvl24i57aef4vc7bbdk9mvj7sic9dsh64t@4ax.com> <f0afa198-e735-4da1-a16a-82764af3de4dn@googlegroups.com> <36534il81ipvnhog6980r9ln9tdqn5cbh6@4ax.com> |
Am 20.04.2023 um 22:44 schrieb George Neuner: > On Thu, 20 Apr 2023 09:45:59 -0700 (PDT), Rick C >> CRC is not complicated, but I would not know how to calculate an >> inserted value to force the resulting CRC to zero. How do you do >> that? > > It's implicit in the equation they chose. I don't know how it works - > just that it does. It works for any CRC that starts with zero and does not invert. CRC is based on polynomial division remainders. Basically, the CRC is a division remainder of the input interpreted as a polynomial, and if you add that remainder back into the equation, result is zero. https://crccalc.com/?crc=12345678&method=CRC-16/AUG-CCITT&datatype=hex&outtype=0 -> result is 0xBA3C https://crccalc.com/?crc=12345678BA3C&method=CRC-16/AUG-CCITT&datatype=hex&outtype=0 -> result is 0x0000 (Need to be careful with byte orders; for some CRCs on that page, you need to swap the bytes before appending.) Stefan
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Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-19 19:06 -0700
Re: Embedding a Checksum in an Image File Niklas Holsti <niklas.holsti@tidorum.invalid> - 2023-04-20 12:14 +0300
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-20 06:18 -0700
Re: Embedding a Checksum in an Image File "Peter Heitzer" <peter.heitzer@rz.uni-regensburg.de> - 2023-04-20 11:30 +0000
Re: Embedding a Checksum in an Image File dalai lamah <antonio12358@hotmail.com> - 2023-04-20 13:47 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-20 06:04 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-20 16:46 +0200
Re: Embedding a Checksum in an Image File George Neuner <gneuner2@comcast.net> - 2023-04-20 11:33 -0400
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-20 09:45 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-20 22:26 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 18:36 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 09:12 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 10:35 +0200
Re: Embedding a Checksum in an Image File George Neuner <gneuner2@comcast.net> - 2023-04-20 16:44 -0400
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-04-20 22:37 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-21 12:43 +0200
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-04-21 04:39 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-21 16:50 +0200
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-04-21 17:29 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-22 16:57 +0200
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-04-24 00:32 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-24 16:37 +0200
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-05-03 00:15 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-05-03 14:48 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-05-09 20:42 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-05-10 10:06 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-05-10 12:03 +0200
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-08-05 01:48 -0700
Re: Embedding a Checksum in an Image File Don Y <blockedofcourse@foo.invalid> - 2023-08-05 01:42 -0700
Re: Embedding a Checksum in an Image File Stefan Reuther <stefan.news@arcor.de> - 2023-04-21 19:40 +0200
Re: Embedding a Checksum in an Image File Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-20 20:17 +0300
Re: Embedding a Checksum in an Image File George Neuner <gneuner2@comcast.net> - 2023-04-20 16:49 -0400
Re: Embedding a Checksum in an Image File Richard Damon <Richard@Damon-Family.org> - 2023-04-20 22:09 -0400
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-20 19:41 -0700
Re: Embedding a Checksum in an Image File Richard Damon <Richard@Damon-Family.org> - 2023-04-21 19:30 -0400
Re: Embedding a Checksum in an Image File Brian Cockburn <brian.cockburn.1959@gmail.com> - 2023-04-21 01:53 -0700
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-21 05:12 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-21 17:02 +0200
Re: Embedding a Checksum in an Image File Brian Cockburn <brian.cockburn.1959@gmail.com> - 2023-04-21 16:56 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-22 17:01 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-21 20:14 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-22 17:13 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-22 09:56 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-22 19:54 +0200
Re: Embedding a Checksum in an Image File Grant Edwards <invalid@invalid.invalid> - 2023-04-22 20:05 +0000
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-23 17:37 +0200
Re: Embedding a Checksum in an Image File Grant Edwards <invalid@invalid.invalid> - 2023-04-23 17:37 +0000
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-23 23:45 +0200
Re: Embedding a Checksum in an Image File Richard Damon <Richard@Damon-Family.org> - 2023-04-23 18:16 -0400
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-24 09:13 +0200
Re: Embedding a Checksum in an Image File boB <boB@K7IQ.com> - 2023-04-22 13:41 -0700
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-23 10:34 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-23 23:58 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-23 15:24 -0700
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-24 09:17 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-24 01:07 -0700
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 18:42 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 09:20 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 10:44 +0200
Re: Embedding a Checksum in an Image File Brian Cockburn <brian.cockburn.1959@gmail.com> - 2023-04-21 16:52 -0700
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-21 20:23 -0700
Re: Embedding a Checksum in an Image File Brian Cockburn <brian.cockburn.1959@gmail.com> - 2023-04-22 07:07 -0700
Re: Embedding a Checksum in an Image File Richard Damon <Richard@Damon-Family.org> - 2023-04-22 10:31 -0400
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-22 09:54 -0700
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 18:26 +0200
Re: Embedding a Checksum in an Image File Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-27 10:09 -0700
Re: Embedding a Checksum in an Image File Niklas Holsti <niklas.holsti@tidorum.invalid> - 2023-04-27 21:29 +0300
Re: Embedding a Checksum in an Image File Niklas Holsti <niklas.holsti@tidorum.invalid> - 2023-04-27 21:39 +0300
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 22:44 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 09:38 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 10:50 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 15:04 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-29 23:03 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-30 16:19 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-05-09 20:34 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-05-10 10:18 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 09:33 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 22:36 +0200
Re: Embedding a Checksum in an Image File Niklas Holsti <niklas.holsti@tidorum.invalid> - 2023-04-28 01:10 +0300
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 10:54 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 09:24 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 10:56 +0200
Re: Embedding a Checksum in an Image File David Brown <david.brown@hesbynett.no> - 2023-04-28 15:09 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-29 23:02 +0200
Re: Embedding a Checksum in an Image File Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 18:27 +0200
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