Template:Fw checksum summary
A checksum is a sequence of hexadecimal symbols generated after running an algorithm called a cryptographic hash function on a file. Calculating a checksum and comparing it with the one provided by the file source can be used as a file authenticity check method.
For example, if you download a file like a firmware image, you should be able to calculate that file's checksum and, if the file is authentic, the checksum should match the one provided by the file's source. If the checksums don't match, it means the file's contents were tampered with, for example, by a malicious third party attacker. This file could probably be dangerous and shouldn't be trusted.