Re: Size of a CRC (or similar) code for a given length of message

From	James Harris <james.harris.1@gmail.com>
Newsgroups	comp.programming
Subject	Re: Size of a CRC (or similar) code for a given length of message
Date	2015-09-25 13:49 +0100
Organization	A noiseless patient Spider
Message-ID	<mu3fp2$sd9$2@dont-email.me> (permalink)
References	<mu35qo$o6g$1@dont-email.me> <f8ccb7b2-963c-4480-a180-8967c61d35cd@googlegroups.com> <mu3f16$qbf$1@dont-email.me>

Show all headers | View raw

On 25/09/2015 13:36, David Brown wrote:
> On 25/09/15 13:17, Öö Tiib wrote:

...

>> CRC is just a cheap filter that lets you discard most of messages
>> that have been corrupted in transit. However what prevents it being
>> maliciously corrupted or corrupted by defect before CRC was added?
>> So It can not replace other integrity and sanity checks.
>
> A CRC check makes it highly unlikely that the message has been corrupted
> without detection during that particular part of its journey.  It says
> nothing about what happened before it is added, or what happens after
> the CRC has been checked - surely that is obvious to the OP, even if he
> has not used CRC's before?

Yes. At least I read that before posting. Guarding against malicious 
tampering is another issue - and not directly relevant just now.

James

Back to comp.programming | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Size of a CRC (or similar) code for a given length of message James Harris <james.harris.1@gmail.com> - 2015-09-25 10:59 +0100
  Re: Size of a CRC (or similar) code for a given length of message David Brown <david.brown@hesbynett.no> - 2015-09-25 13:05 +0200
    Re: Size of a CRC (or similar) code for a given length of message James Harris <james.harris.1@gmail.com> - 2015-09-25 13:42 +0100
      Re: Size of a CRC (or similar) code for a given length of message David Brown <david.brown@hesbynett.no> - 2015-09-25 15:15 +0200
  Re: Size of a CRC (or similar) code for a given length of message Julio Di Egidio <julio@diegidio.name> - 2015-09-25 04:07 -0700
    Re: Size of a CRC (or similar) code for a given length of message David Brown <david.brown@hesbynett.no> - 2015-09-25 14:32 +0200
      Re: Size of a CRC (or similar) code for a given length of message Julio Di Egidio <julio@diegidio.name> - 2015-09-25 05:40 -0700
    Re: Size of a CRC (or similar) code for a given length of message James Harris <james.harris.1@gmail.com> - 2015-09-25 13:45 +0100
  Re: Size of a CRC (or similar) code for a given length of message Öö Tiib <ootiib@hot.ee> - 2015-09-25 04:17 -0700
    Re: Size of a CRC (or similar) code for a given length of message David Brown <david.brown@hesbynett.no> - 2015-09-25 14:36 +0200
      Re: Size of a CRC (or similar) code for a given length of message James Harris <james.harris.1@gmail.com> - 2015-09-25 13:49 +0100

csiph-web