A checksum is a value created from a binary file that can be used to validate its authenticity and integrity. An example of a checksum is MD4, MD5 and SHA-1.

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980 views

Is verifying a MD5 sum after copying 100GB of data safe?

I'm copying 100GB from a Windows 7 workstation to 2 external drives (if you have only one backup, then you have none). All files have a MD5 checksum. I've verified all MD5 checksums on the external ...
8
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3answers
3k views

What are these Google SHA1 images? [closed]

If you look at this page you'll see an monochrome image. Above it says Tip: Use the SHA1 checksum shown to verify file integrity. However, I don't know if that's related. What are these ...
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5answers
630 views

Does recompiling a program produce a bit-for-bit identical binary?

If I were to compile a program into a single binary, make a checksum, and then recompile it on the same machine with the same compiler and compiler settings and checksum the recompiled program, would ...
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6answers
210 views

Checksum for Protecting Read-Only Documents

My father owns a small business and has to hand over several year's worth of financial documents to his insurance's auditor. He's asked me to go through and make sure everything is "read-only" so the ...
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1answer
488 views

Does Windows calculate CRCs to check every file operation?

When Windows encounters a file corruption on a file system, it may return the following error message: Data error (cyclic redundancy check). This suggests Windows checks every file operation ...
5
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1answer
1k views

File copy program that generates checksums of the data while copying too

My question in short: is there a tool that copies a file from directory A to B while, simultaneously, generating the checksum of the file it has copied/read, without doing an extra read/pass just to ...
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3answers
1k views

Is there anything like HashTab for Linux?

I've recently installed Linux, and I know that you can use "md5sum filename" in terminal, but on Windows there is an AMAZING software called HashTab that incorporates it into the shell. Its awesome, ...
4
votes
2answers
293 views

Mass Checksumming tool for Windows?

I'm looking for a command line tool for windows that will go over a directory tree (recursively) and output a list of all the files in there, and a checksum for each file (can be CRC, MD5, whatever). ...
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4answers
3k views

Single unix command to correctly transfer a large file?

I am trying to transfer a large (~3GB) file between two unix machines. I can use scp or rsync, but sometimes the transfer is corrupted. (I have to check manually.) I can split the file into pieces ...
3
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2answers
562 views

TCP Checksum, why?

Why does TCP need a checksum, when lower layers do integrity checks anyways (like Ethernet CRC)?
3
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3answers
1k views

How does a downloaded ISO get corrupted? [duplicate]

Possible Duplicate: Is it possible to get corrupted download with http? I downloaded an ISO for fedora. Went to install it as a VM. It failed 5 times the installer. The warning for the ...
3
votes
1answer
390 views

Is there a utility to verify the checksums of every Windows file?

I would like to know if there is a utility to verify the checksums of every Windows file on my Windows 7 Ultimate system. It seems on the surface such an obvious utility but I don't ever remember ...
3
votes
1answer
1k views

What is the best way to make Calculate SHA1 as a context menu option in Mac OS X?

In order to calculate the SHA1 checksum of a downloaded file, I could type /usr/bin/openssl sha1 in Terminal and then drag there the file which I want check. To make it simpler, one could enable a ...
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3answers
2k views

A gigabit network interface is CPU-limited to 25MB/s. How can I maximize the throughput?

I have a Acer Aspire R1600-U910H with a nForce gigabit network adapter. The maximum TCP throughput of it is about 25MB/s, and apparently it is limited by the single core Intel Atom 230; when the ...
2
votes
4answers
204 views

Why would I check my download against a checksum provided by a mirror site?

I thought the point of distributing md5 checksums was so the end user could verify the integrity of the download. If a high traffic site points me to a mirror site for download, why would I want to ...
2
votes
3answers
232 views

How do I check the checksum of a download and why should I?

My memory isn't great but I think five or six years ago, when I downloaded some package, there was never a checksum line under the download icon on the webpage. And no instructions to "check the ...
2
votes
2answers
2k views

Is it possible to download corrupted torrent files, even with a download client builtin checksum verification?

I downloaded some mkv/mp4 files with my new router (I can download directly from it, using transmission), and all of them seem to be corrupted: lags, strange artifacts when using vlc, crashes with ...
2
votes
2answers
224 views

HTTP downloader with good integrity(hash..probably md5) checker built in [closed]

I'm trying to download xcode v3.2 from the Apple Developer Connection website, but everytime I download the huge file, it fails to mount due to a checksum error. It's really frustrating! BitTorrent ...
2
votes
1answer
2k views

How is TCP/UDP checksum working?

I used raw socket to create some UDP packets and then send them to a UDP server I notice that when I put a wrong UDP checksum number the UDP server doesn't accept it, but if I put all 0 on the ...
2
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2answers
567 views

Undeletable Folders [duplicate]

Possible Duplicate: Windows Updates Folders (With Strange Names) in C drive I have 3 Folders on my D: - Drive they seem to be auto-generated by Windows their names are: ...
2
votes
2answers
1k views

How do downloads become corrupt? (SHA1 value varies)

I downloaded VS 2012 using IDM. While I did pause and resume several times, it downloaded successfully. BUT, the SHA1 and CRC values do not match with the given values in the website. This means that ...
2
votes
2answers
2k views

Checksumming an entire CD/DVD

I'm publishing a set of documentation to be delivered on CD. My Company's European production manager is concerned that he has no way to verify that the data on the discs he produces is correct. He ...
2
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2answers
652 views

Verification of files on backup media - after the backup

I have a system in place where I back up my work files daily to a portable hard drive. I actually have two portable hard drives - one is stored off-site and I swap them regularly. I also keep my ...
2
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1answer
202 views

Hardware digital signature

Is it possible to show how generate a digital signature, a checksum, or something along those lines based on your computer hardware using an Ubuntu Live CD? So, once the first digital signature is ...
2
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2answers
1k views

Looking for OS X utility to verify/validate copied files/directories - checksum / SFV / MD5

Looking for the best way to easily validate the integrity of files/folder in OS X when copied from one location to another. I've downloaded SuperSFV but it appears to be very slow. Also new to the ...
2
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1answer
187 views

md5sum only new files?

I have a directory containing files and an md5sum.txt file. I add a file new files to the directory. I would like add md5sum sums for all files that are not in md5sum.txt. Is there a simple way to do ...
2
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1answer
929 views

recursive file/directory verification on linux

What would be a command structure or simple bash script to run to compare all files in one directory with all files in another directory, verifying their data are identical, or not, down to the bit? ...
2
votes
1answer
2k views

Is it possible to check a PDF for data corruption?

I have some PDF documents and I'd like to check them for possibile data corruption, even if I'm able to display them without problems. I don't really know if PDF documents store an embedded checksum ...
2
votes
2answers
4k views

Keyboard error or no keyboard present

I've been fighting with this for a couple of weeks when booting my PC: Error keyboard or no keyboard present CMOS checksum error -Default loaded And of course there is no way to go any further ...
2
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1answer
92 views

File corruption detection strategy

due to current high price of hdds, I would like to switch from running RAID1 to JBOD + offsite backup (Backblaze). In theory it's a much better approach (if PC gets fried by lighting strike, I still ...
2
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0answers
80 views

MD5 for Git's git-credential-osxkeychain executable? [closed]

I'm setting up a GitHub account and have downloaded Git's credential-osxkeychain executable via the Password Caching section of GitHub's instructions. But... I am paranoid enough to look for some ...
2
votes
1answer
73 views

Backup solution: hash/checksumming and/or error correction

I'm trying to keep my data well protected with backups, using multiple hard drives (basically swapping the backup disk out every week). For checking validity, I was originally planning on md5summing ...
2
votes
1answer
639 views

Is it possible to check a FLV for data corruption?

I have some FLV videos and I'd like to check them for possibile data corruption, even if I'm able to play them without problems. I don't really know if FLV videos store an embedded checksum string for ...
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2answers
3k views

“CMOS check sum error” while booting

I am using an HCL desktop system (Core 2 Duo, 1 GB RAM, Windows XP SP2). While booting I got the following message. CMOS check sum error. Press f1 to continue When pressing F1 it is working ...
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3answers
281 views

tool for maintain incrementally the checksum of a large set of files

I need a tool to generate and maintain the checksum (MD5, SHA1, it does not matter) of all files in a folder or a set of folders, recursively. Sometimes I will add/update/remove some files and I ...
1
vote
2answers
130 views

how to backup only files paths, names, sizes and checksums?

I'm looking for an application which will allow me to select some folders, and then regularly backup only complete paths, names, sizes and checksums of the files within those folders and their ...
1
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1answer
110 views

Can I rely on CDs and DVDs for storage when I copy them without errors?

I have old CD and DVDs. I am copying the files I have on these discs to my hard drive, but can I be sure that these files are not broken? I copy these files with no errors and don't want to keep the ...
1
vote
1answer
147 views

sourceforge checksums: Where are they? [closed]

I've been particular about checksumming all downloaded software. Today, trying to download from Sourceforge, I could not find any checksums for the projects. Am I just missing them or are they not ...
1
vote
1answer
222 views

Tool to maintain/keep track of filesystem content integrity?

I'm looking for a tool to maintain the integrity of a filesystem and it's contents using checksums. Effectively storing a list of checksums/filename pairs somewhere on the filesystem in a way that can ...
1
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1answer
85 views

What does my computer do if it receives a data-packet with a wrong checksum?

Since modern routers don't check the header-checksum any more to increase performance I'm wondering what my computer is doing with defective data-packets? Further reading links appreciated.
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3answers
3k views

How can I copy files to an external drive and verify their integrity in OS X?

I'm moving large amounts of data from one external drive to another larger one. The files are important and the smaller drives need to be cleared and reused (HD camera). Is there some utility for ...
1
vote
1answer
132 views

On Mac, after downloading a file, how to you do a checksum?

I want to do a checksum on a file I downloaded on my Mac. How can I do this?
1
vote
1answer
484 views

Windows 8.1 Checksum

I've looked all over for the sha-1 or sha-256 checksum for the windows 8.1 iso that you get with the Microsoft’s “Upgrade Windows with only a product key” page but none of the check sums provided on ...
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vote
1answer
557 views

How to get rid of UDP checksum error messages in virtual console?

Whenever I am streaming a video in the web browser, while connected to my school LAN via ethernet, and switch to the virtual console (ctrl-alt-f1) on Ubuntu, I get an error that looks like the ...
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vote
2answers
398 views

Calculate checksum of file from right-click menu? [duplicate]

Possible Duplicate: Looking for MD5 utility that integrates to Windows What would be the easiest way to have the checksum of a file shown in a message box using the right click menu on the ...
1
vote
3answers
352 views

Merge two Foldes (Backups from my Files) on Windows 7 or Ubuntu 12.04

I have yearly backups of all my files on the harddrive. The problem is that the Backup from 2007 contains files which don't exist in 2008. And I need both Versions of the Files, when they are ...
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3answers
885 views

Solution for noisy network that corrupts downloaded files

The network on the company where my wife works sucks BIG TIME. Almost every single file bigger then a few hundred kB is corrupted during download and even web pages are sometimes garbled. We checked ...
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0answers
119 views

Window Vista cannot create new folder, note, etc when right click and recent items forever empty after crashes

Basically my computer crashes and after I reboot I got a checksum error, so I reboot again and these problems appears: 1):Unable to create new folder, notes, zip file,etc. (when I right click in ...
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0answers
82 views

Cannot open an encrypted file on OS X

I cannot decrypt files on OS X (10.6.8 and 10.8.2) which I have encrypted on Ubuntu (10.04) using ccrypt. As a similar problem, I have a password file created with KeePassX. I just cannot open it on ...
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3answers
245 views

How do I verify the authenticity of a linux system executable?

I'm aware of md5sum and gpg but I have no idea if there are recorded checksums for whatever current version of ubuntu is installed. Do these get recorded somewhere? Specifically I'm suspicious that ...