This post is mostly about Security Hash Algoritms and how you can use them to verify the integrity of your files.

SHA1

Let’s say you downloaded something. The website had a sha1sum there and you want to verify that you actually got the file you wanted – and not some tampered malware. Checking is as easy as writing:

sha1sum <filename> .

Or if you want to verify a checksum even more easily, pipe it and use grep.

sha1sum <filename> | grep <checksum_listed_on_the_page> .

If you get the hash as an output that usually means that things are ok. If you get nothing then there is a mismatch.

SHA256 Continue reading →