userguide:checking_iso_file_integrity

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userguide:checking_iso_file_integrity [2016/04/23 23:26]
Marc created
userguide:checking_iso_file_integrity [2020/11/26 19:49] (current)
Marc
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 In simple terms, a //[[https://en.wikipedia.org/wiki/Checksum|checksum]]// or //hash sum// is like a signature or fingerprint that identifies digital data. A copy of a file getting the same computed checksum as the original indicates there is a very high probability the data has not been accidentally altered or corrupted((Security flaws where identified in MD5 and SHA-1 algorithms; they are still useful for error checking, where data tampering is not a primary concern, but the use of stronger hash functions would be desirable.)). In simple terms, a //[[https://en.wikipedia.org/wiki/Checksum|checksum]]// or //hash sum// is like a signature or fingerprint that identifies digital data. A copy of a file getting the same computed checksum as the original indicates there is a very high probability the data has not been accidentally altered or corrupted((Security flaws where identified in MD5 and SHA-1 algorithms; they are still useful for error checking, where data tampering is not a primary concern, but the use of stronger hash functions would be desirable.)).
  
-Checking NethServer's ISO image file takes almost no time and prevents further installation problems.+Checking NethServer's ISO image file takes almost no time and prevents further installation problems. Checksums for the ISOs can be found at the [[https://www.nethserver.org/getting-started-with-nethserver/|download page]]. 
 + 
 +The following examples show different ways to check the integrity of a file.  
 +Bear in mind the checksums and ISO names mentioned in the examples may differ from the current NethServer release.
  
-The following examples show different ways to check the integrity of a file. 
  
 ===== File Integrity Check from an On-Line Service ===== ===== File Integrity Check from an On-Line Service =====
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 There are some on-line services that do the file verification on the client-side, without uploading the file to their servers. One of them is [[http://www.toolsley.com/hash.html|Toolsley Hash & Validate]] browser-based service, which can be used from GNU/Linux, OS X, Windows and other Operating Systems. There are some on-line services that do the file verification on the client-side, without uploading the file to their servers. One of them is [[http://www.toolsley.com/hash.html|Toolsley Hash & Validate]] browser-based service, which can be used from GNU/Linux, OS X, Windows and other Operating Systems.
  
-//Video: Checking NethServer's ISO Image File Integrity using an On-Line Service//+{{ youtube>QwAqRn_XDew?medium }}\\ 
 + 
 +---- 
  
 ===== File Integrity Check from a Graphical User Interface Program ===== ===== File Integrity Check from a Graphical User Interface Program =====
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 The next examples show how to use some file integrity checkers on different Operating Systems. The next examples show how to use some file integrity checkers on different Operating Systems.
  
-**DownThemAll! Firefox web browser add-on** (works on GNU/Linux, OS X, Windows)\\ //[[https://addons.mozilla.org/firefox/addon/downthemall/|DownThemAll!]]// Firefox add-on is an Open Source download manager that integrates into [[https://www.mozilla.org/firefox/new/|Mozilla Firefox]] web browser. Its built-in checksum (hash verification) support allow you to download a file and verify its integrity in the same step, without leaving the web browser.+**DownThemAll! Firefox web browser add-on** (works on GNU/Linux, OS X, Windows)\\ //[[https://addons.mozilla.org/firefox/addon/downthemall/|DownThemAll!]]// Firefox add-on is an Open Source download manager that integrates into [[https://www.mozilla.org/firefox/new/|Mozilla Firefox]] web browser. Its built-in checksum (hash verification) support allows you to download a file and verify its integrity in the same step, without leaving the web browser.
  
 In short, the operation process has these steps: In short, the operation process has these steps:
  
-  Get the file checksum/hash from the original source\\  +  Get the file checksum/hash from the original source\\  
-  Choose the file to be downloaded (NethServer's ISO image)\\  +  Choose the file to be downloaded (NethServer's ISO image)\\  
-  Choose //DownThemAll!// as the download manager\\  +  Choose //DownThemAll!// as the download manager\\  
-  Paste the checksum in the appropriate //DownThemAll!// text field\\  +  Paste the checksum in the appropriate //DownThemAll!// text field\\  
-  Start the download+  Start the download 
 + 
 +{{ youtube>ochWBOdayK8?medium }}\\
  
 Once the file has been downloaded, //DownThemAll!// will verify it against the hash provided previously. In case of a hash mismatch, a dialog will appear informing you of the failure and will give you the option to retry the download, keep the file, or delete the file. Once the file has been downloaded, //DownThemAll!// will verify it against the hash provided previously. In case of a hash mismatch, a dialog will appear informing you of the failure and will give you the option to retry the download, keep the file, or delete the file.
  
-//VideoChecking NethServer's ISO Image File Integrity using DownThemAll! Firefox add-on//+{{ :howto:downthemall-hash-mismatch.png |DownThemAll! hash mismatch notification}}\\ 
 + 
 + 
 +----
  
 **MultiHasher** (works on Windows)\\ //[[http://www.abelhadigital.com/multihasher|MultiHasher]]// is a freeware file hash calculator. It has an installable version and a portable one. //MultiHasher// can be integrated into Windows Explorer context menu. **MultiHasher** (works on Windows)\\ //[[http://www.abelhadigital.com/multihasher|MultiHasher]]// is a freeware file hash calculator. It has an installable version and a portable one. //MultiHasher// can be integrated into Windows Explorer context menu.
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 Its association with the most common file extensions used to distribute hashes makes it very simple to use. You just have to download NethServer's ISO image file and its computed file hash (i.e. MD5, SHA1...) on the same folder. Once the files are in place, opening the checksum file will bring up the //MultiHasher// program, that in turn will verify the integrity of the ISO image file against it. Its association with the most common file extensions used to distribute hashes makes it very simple to use. You just have to download NethServer's ISO image file and its computed file hash (i.e. MD5, SHA1...) on the same folder. Once the files are in place, opening the checksum file will bring up the //MultiHasher// program, that in turn will verify the integrity of the ISO image file against it.
  
-//Video: Checking NethServer's ISO Image File Integrity using MultiHasher//+{{ youtube>9MkJ8LiB_g8?medium }}\\ 
 + 
 +----
  
 **GtkHash** (works on GNU/Linux)\\ //[[http://gtkhash.sourceforge.net/|GtkHash]]// is //Free Software// for computing message digests or checksums. It can be installed from the Software/Package Manager of most GNU/Linux distributions. **GtkHash** (works on GNU/Linux)\\ //[[http://gtkhash.sourceforge.net/|GtkHash]]// is //Free Software// for computing message digests or checksums. It can be installed from the Software/Package Manager of most GNU/Linux distributions.
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 There are additional packages you can install to integrate //GtkHash// into multiple file managers like //Nautilus//, //Nemo//, and //Thunar//. There are additional packages you can install to integrate //GtkHash// into multiple file managers like //Nautilus//, //Nemo//, and //Thunar//.
  
-//VideoChecking NethServer'ISO Image File Integrity using gtkHash//+{{ youtube>6aCu9GKI298?medium }}\\ 
 + 
 +---- 
 + 
 +**7-Zip** (works on Windows)\\ Althought //[[http://www.7-zip.org/|7-Zip]]// is a file archiver, it adds a //CRC, SHA...// context menu entry to ISO image files. This menu allows you to compute the hashes and visually compare them against the original ones. //7-Zip// is //Open Source// software. 
 + 
 +{{ :howto:iso-image-file-integrity-check-using-7zip-checksuming-hashing.jpg?direct&420 |7-Zip context menu and hashing}} 
 + 
 +----
  
 ===== File Integrity Check from the Command-Line ===== ===== File Integrity Check from the Command-Line =====
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 Example: Example:
  
-<code>openssl md5 nethserver-6.7-x86_64.iso</code>+<code>openssl md5 nethserver-7.9.2009-x86_64.iso</code>
 This command will output a computed file hash that can be manually compared against the original one: This command will output a computed file hash that can be manually compared against the original one:
  
-<code>MD5(nethserver-6.7-x86_64.iso) = 695ac8fe87b21501cc438abc411d8f02</code>+<code>MD5(nethserver-7.9.2009-x86_64.iso) = 6a32d2738aafdcf4e124c2822e5c668d</code>
 On **Mac OS X**, you can also use the ''%%md5%%'' command to get the same result: On **Mac OS X**, you can also use the ''%%md5%%'' command to get the same result:
  
-<code>md5 nethserver-6.7-x86_64.iso</code>+<code>md5 nethserver-7.9.2009-x86_64.iso</code>
 On **GNU/Linux**, you can also get the MD5 file hash using the ''%%md5sum%%'' command, On **GNU/Linux**, you can also get the MD5 file hash using the ''%%md5sum%%'' command,
  
-<code>md5sum nethserver-6.7-x86_64.iso +<code>md5sum nethserver-7.9.2009-x86_64.iso 
-695ac8fe87b21501cc438abc411d8f02  nethserver-6.7-x86_64.iso</code>+6a32d2738aafdcf4e124c2822e5c668d  nethserver-7.9.2009-x86_64.iso</code>
 and if you have downloaded the original MD5 file hash to the same folder as NethServer's ISO image, you can use ''%%md5sum%%'' command to check its integrity: and if you have downloaded the original MD5 file hash to the same folder as NethServer's ISO image, you can use ''%%md5sum%%'' command to check its integrity:
  
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 Example: Example:
-<code>md5sum --check nethserver-6.7-x86_64.iso.md5 +<code>md5sum --check nethserver-7.9.2009-x86_64.iso.md5 
-nethserver-6.7-x86_64.iso: OK</code>+nethserver-7.9.2009-x86_64.iso: OK</code>
 **Getting and comparing SHA1 checksums**\\ In both, GNU/Linux and Mac OS X Operating Systems, you can use ''%%openssl%%'' or ''%%shasum%%'' command to get the SHA1 hash of a file: **Getting and comparing SHA1 checksums**\\ In both, GNU/Linux and Mac OS X Operating Systems, you can use ''%%openssl%%'' or ''%%shasum%%'' command to get the SHA1 hash of a file:
  
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 ''%%openssl%%'' example: ''%%openssl%%'' example:
  
-<code>openssl sha1 nethserver-6.7-x86_64.iso +<code>openssl sha1 nethserver-7.9.2009-x86_64.iso 
-SHA1(nethserver-6.7-x86_64.iso)= 1e4d822b92d391c2f5d93f33af8a034cdcf2cf7e</code>+SHA1(nethserver-7.9.2009-x86_64.iso)= 9e3e67f13328163cfd383d1e0fcb7288eed282b8</code>
 ''%%shasum%%'' example: ''%%shasum%%'' example:
  
-<code>shasum nethserver-6.7-x86_64.iso +<code>shasum nethserver-7.9.2009-x86_64.iso 
-1e4d822b92d391c2f5d93f33af8a034cdcf2cf7e  nethserver-6.7-x86_64.iso</code>+9e3e67f13328163cfd383d1e0fcb7288eed282b8  nethserver-7.9.2009-x86_64.iso</code>
 If you have downloaded the original SHA1 file hash to the same folder as NethServer's ISO image, you can check its integrity with the ''%%shasum%%'' command: If you have downloaded the original SHA1 file hash to the same folder as NethServer's ISO image, you can check its integrity with the ''%%shasum%%'' command:
  
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 Example: Example:
  
-<code>shasum --check nethserver-6.7-x86_64.iso.sha1 +<code>shasum --check nethserver-7.9.2009-x86_64.iso.sha1 
-nethserver-6.7-x86_64.iso: OK</code>+nethserver-7.9.2009-x86_64.iso: OK</code>
 On **GNU/Linux**, you can also use the ''%%sha1sum%%'' command in place of ''%%shasum%%''. On **GNU/Linux**, you can also use the ''%%sha1sum%%'' command in place of ''%%shasum%%''.
  
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 Alternative programs might exist on each Operating System. Alternative programs might exist on each Operating System.
  
-{{tag>ht_installation}}+{{tag>ht_installation userguide before_installation}}
  • userguide/checking_iso_file_integrity.1461454005.txt.gz
  • Last modified: 2016/04/23 23:26
  • by Marc