Sooner or later you or your company will have to send, share, sell or publish a digital file. Then, you will have to be sure that file will maintain its integrity once it's received or downloaded by a customer, a collaborator, a company, a friend, etc.
In this case you have no chance but to calculate the hash of that file. At the same time, who receives or download the file, should be able to verify the file’s integrity.

For example, imagine that you will send a sensitive PDF file to an important customer. Both of you need to know to have to do with the very same file. Files Integrity is the answer! You will create a hash of the file, the customer will verify its integrity!

* Creating a hash of a file:

Select the encryption type: MD5 or SHA-1. Then, select “Create” and drag a file from the Finder and drop it on the highlighted box.

Just below the box you will see the file’s hash. You can copy and paste it where you want, such as where you compose your e-mails, or on your messenger when chatting, on your website, etc.

* Verifying a file’s integrity

Select the encryption type: MD5 or SHA-1. Then, select “Verify” and paste the hash of the file, whose integrity you want to check.
Now, drop the file on the highlighted box: just below the box you will get the verification result.

* In addition, you can generate a GUID!

A globally unique identifier is a unique reference number used as an identifier in computer software. The term GUID also is used by various implementations of the Universally unique identifier (UUID) standard.
The value of a GUID is represented as a 32-character hexadecimal string, such as {21EC2020-3AEA-1069-A2DD-08002B30309D}, and is usually stored as a 128-bit integer. The total number of unique keys is 2128 or 3.4×1038. This number is so large that the probability of the same number being generated randomly twice is negligible; however, GUID numbers are not always generated randomly.