HelpSystems uses the MD5 cryptographic hash function to help verify the integrity of product downloads. The MD5 message-digest algorithm is a widely used hash function producing a 128-bit (16-byte) hash value, typically expressed as a 32-digit hexadecimal number. MD5 is used in a wide variety of cryptographic applications and in the software industry at large to provide some assurance that a transferred file has arrived intact.
You can click the MD5 link adjacent to a HelpSystrems download to reveal its hash value.
The hash value is a pre-computed checksum that can be compared with the checksum of the downloaded file to verify the file has not been compromised during the transfer. There are many MD5 hash checkers available on the web that allow you to do this. They can be found for any Operating System that uses the MD5 algorithm. Some are GUI based and others are command line driven. Two examples are listed below.
MD5 Checksum Utilities
MD5 & SHA Checksum Utility is a standalone freeware tool that generates and verifies cryptographic hashes in MD5, and includes an easy-to-use GUI.
md5deep is an example of a command line, open-source Windows MD5 checking program. Once you have installed it, you can use the md5deep.exe to calculate the hash (e.g. md5deep.exe HS_CD1_2014_APRIL30.iso). Compare that string with the one provided for the HelpSystems download. Most programs like md5deep allow you to check one or more MD5 hash strings from a file containing known hashes.
Review the documentation for the above tools for additional information.