WordPress themes allows each WordPress site to look unique. Many WordPress sites use the same theme, but the look and feel of the theme can be customized. Since most sites use 3rd party themes, they’re also the most common target for malicious attacks. The wp-md5 WordPress theme checksum database can be used to compare good, known md5 checksums in our database to the checksums of the theme files on your server. The md5sum of every plugin on WordPress.org is available here, and can be accessed in an automated manner by using the following url scheme:
https://wpmd5.mattjung.net/theme/theme_slug/theme_version/
So for example, to get the md5sums of the files for version 2.5.3 of the storefront theme, you would access them at the following location:
https://wpmd5.mattjung.net/theme/storefront/2.5.3/
You can also browse all theme checksums here.