Security+:- md5 check sum

Checking file integrity with md5.

On Windows machine

1. Create a directory on your windows machine
C:\Users\sam\Desktop\md5>

2. Download the md5sum application from internet.eg,
https://www.microsoft.com/en-us/download/details.aspx?id=11533

3. Create a myhashFile.txt file and add the content "Testing md5 checksum with the utility!!!"
4. Now run the md5 application to genetate the hashing algorithm.

C:\Users\sam\Desktop\md5>dir

05/27/2015  11:40 AM    <DIR>          .
05/27/2015  11:40 AM    <DIR>          ..
05/13/2004  01:26 PM            84,784 fciv.exe
05/27/2015  11:44 AM                42 myhashFile.txt
05/13/2004  01:26 PM             3,627 ReadMe.txt
               3 File(s)         88,468 bytes
               2 Dir(s)  420,039,544,832 bytes free


C:\Users\sam\Desktop\md5>fciv.exe myhashFile.txt
0c4e7e7f69128d826092ed20d4fecf5a myhashfile.txt

You can run multiple time to compare the output but you will find the same result.

5. Now, edit a file and add some extra content say "I modify file"
type notepad myhashfile.txt and it will open notepad.

Re-run the md5 check command.

C:\Users\sam\Desktop\md5>fciv.exe myhashFile.txt
264e9b0f8e37ded3b39e38b6695b658c myhashfile.txt

Now, the output is different than the previous one.

This is tell you if file/data is modify somewhere while downloading ..

On Linux

Just run the md5 command followed by a file name
$ md5sum createUser.sh
4fca82ac747f49b968828087de061f20  createUser.sh