GO supports file based authentication, refer : http://www.thoughtworks-studios.com/docs/go/12.1/help/dev_authentication.html
Password are hashed with SHA1 and encoded with base 64. To generate such passwords you can use: http://www.insidepro.com/hashes.php?lang=eng
Note this page provides you a lot of options. To identify the format that works with GO, please navigate to 'SHA-1' and select the second option under . Attached below is the screenshot which show the conversion for the string 'badger'.