Even if OSx is a secure operating system it can become unsecured when you are starting to download files from internet. With this new app you can generate the md5 hash of a file to check if it is the same md5 provided by the source of download and it wasn't corrupted by another person before to be sent to you.
Also you can check if 2 or more files are the same.
Buy this app for a higher level of protection. It saves you the trouble.