Please use CFV python utility as backend - it allows to test and create sha1sum, md5sum, .sfv, .csv, check multiple files, etc.

[Mantas Kriaučiūnas]

Currently nautilus-md5sum allows only md5sum of calculation one .iso file. There are missing lots of usefull features, what you think about adding possibility to check/create md5sum of any file or list of selected files/folders, not just .iso files? It would be very useful feature, for example I very often use command-line cfv utility to create checksums for files, which I write to USB stick or other removable media.

Developer David Amián told me, that in future versions, he plan to extend nautilus-md5sum do more services as create md5sum, compare with .md5sum file, check multiple files....
cfv already have these features, so, you can use cfv as backend, see http://cfv.sourceforge.net :

cfv is a python utility to both test and create .sfv, .csv, .crc, .md5(sfv-like), md5sum, bsd md5, sha1sum, and .torrent files:

    * supports testing and creating of .sfv, .csv(2, 3, and 4 field variants), .crc, sfvmd5(sfv file using md5 instead of crc32), md5sum, bsd md5, sha1sum, and BitTorrent file formats
    * test-only support for PAR and PAR2 files
    * automatic checksum file naming ability in create mode
    * 2 modes of recursive operation (very useful feature, can automatically create separate checksum files in every folder)
    * show unverified files option
    * ignore case and fix path separator options for cross platform use
    * transparent gzip support for checksum files
    * configurable renaming of bad files (with testing against previous bad files, to save only unique differing copies)
    * searching for/fixing of misnamed files
    * raw listing of files of specified type (bad, missing, etc)
    * test suite to ensure correct operation

CFV package is included in Ubuntu and Debian very long time (since 2000) and is actively maintained.