Where can I find info about 2.5’s updated nonce

I have modified a plugin that originally made use of the nonce and check_admin_referer functions. After upgrading to 2.5 users get the message “Are you sure you want to do that?” without any yes or no buttons when submitting a form.

I am familiar with plugin development and feel that I could correct the issue if I knew what changed. Is there documentation on this anywhere.

The original plugin is http://wordpress.org/extend/plugins/wp-photo-album/
My modified version: http://wordpress.org/support/topic/155207?replies=1#post-687611