How to get the MD5/SHA1 Checksum of a file

This is pretty straight forward. As mentioned in an earlier post a MD5 and SHA1 checksum is used to verify that a file was not changed since the author updated it on his/her website.

This is how it’s done on a mac.

1. Open a terminal window

2. Type in the following

For SHA1

 openssl sha1 filename.ext 

For MD5

 openssl md5 filename.ext 

How to get the MD5 Checksum of a file

MD5 Checksum is used to verify the integrity of a file

In other words to make sure a file posted by the author has not been changed by a third party.

To use this the author posts the file and the hash value he got from running a file checksum. The person downloading the file then runs a file checksum on the file when they have it on their computer to see if it matches the authors checksum. If it does, it has not been altered, if it doesnt it has. Read more on this on MD5 Wikipedia.org.

Here is how I got it working on my Windows 7 computer

  1. Download and extract the File Checksum Integrity Verifier utility package
  2. Move the fciv folder to where you please. Rename the file fciv.exe to checksum.exe to make things simpler later.
  3. Add it to the system path for calling it easily later from the command line. Type:
    set path=%path%;c:location_of_fciv_folder
    

And you are done! For additional information read the ReadMe.txt file included in Microsofts download.

Now lets try it by calling the .exe file as such:

checksum.exe [filename]

checksumwin

Update:

I’ve noticed that setting the system path doesn’t seem to be permanent but a per-command-line-window thing.