Path: csiph.com!usenet.pasdenom.info!news.redatomik.org!newsfeed.xs4all.nl!newsfeed8.news.xs4all.nl!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.011 X-Spam-Evidence: '*H*': 0.98; '*S*': 0.00; 'subject:Python': 0.05; 'filesystem': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'hits': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'wrote:': 0.16; 'translation': 0.16; 'byte': 0.18; 'am,': 0.23; 'posted': 0.23; '2015': 0.23; 'header:In-Reply-To:1': 0.24; 'header:User-Agent:1': 0.26; 'header:X-Complaints-To:1': 0.26; 'appending': 0.29; 'description,': 0.29; 'periodic': 0.29; 'routine': 0.29; 'mention': 0.31; 'table': 0.32; 'link.': 0.32; "d'aprano": 0.33; 'received:comcast.net': 0.33; 'steven': 0.33; 'server': 0.34; 'to:addr:python-list': 0.35; 'possible': 0.36; "didn't": 0.37; 'subject:: ': 0.37; 'received:org': 0.38; 'pm,': 0.39; 'does': 0.39; 'to:addr:python.org': 0.39; 'data': 0.40; 'sure': 0.40; 'why': 0.40; 'charset:windows-1252': 0.65; 'subject:Data': 0.66; 'integrity': 0.76; 'smith': 0.76; 'checks.': 0.91 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Randall Smith Subject: Re: Pure Python Data Mangling or Encrypting Date: Mon, 29 Jun 2015 15:52:37 -0500 References: <558b7e85$0$1648$c3e8da3$5496439d@news.astraweb.com> <558bc912$0$2899$c3e8da3$76491128@news.astraweb.com> <558c1a7e$0$1668$c3e8da3$5496439d@news.astraweb.com> <558d86b0$0$1659$c3e8da3$5496439d@news.astraweb.com> <558ef059$0$1673$c3e8da3$5496439d@news.astraweb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Gmane-NNTP-Posting-Host: c-98-251-140-107.hsd1.ms.comcast.net User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 In-Reply-To: <558ef059$0$1673$c3e8da3$5496439d@news.astraweb.com> X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 22 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1435611181 news.xs4all.nl 2968 [2001:888:2000:d::a6]:48410 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:93295 On 06/27/2015 01:50 PM, Steven D'Aprano wrote: > On Sun, 28 Jun 2015 03:08 am, Randall Smith wrote: > >> Though I didn't mention it in the description, the storage server is >> appending a CRC32 checksum for routine integrity checks. So by the time >> the data hits the disk, it will have added both a 256 byte translation >> table and a 4 byte checksum. > > > http://stackoverflow.com/questions/1515914/crc32-collision > > > > Not sure why you posted the link. The crc32 checksum is just to check for possible filesystem corruption. The system does periodic data corruption checks. BTRFS uses crc32 checksums also. Please explain. -Randall