Verify file integrity

by Felix Kinaro About 2 min reading time

File modifications in transit can mean compromise to the security of a system. An attacker may embed malware and exploit unsuspecting end users. File integrity verification using hash functions is the best means to determine if a file has been modified.

What are cryptographic hash functions?

This is a mathematical algorithm that maps an arbitrary size input (message) to a fixed length string value (Message digest).

Ideal hash function

Integrity Verification on Windows

There is no officially supported method of determining file integrity on Windows systems.
The best option is to install the HashCheck Shell Extension.
The extension adds a Checksums entry in the File Properties window
Sample Hash Check

One can then compare the values with those provided by the source of the information.

Integrity verification on GNU/Linux systems

I'm using Ubuntu 18.04, and there are hash functions available out of the box:

You can find detailed information on the Secure hash algorithms page on wikipedia.

Other uses of cryptographic hash functions

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