Sha1 encryption with actionmailer

Hi,

i was wondering wether this was an impossible task, or if there was
something i am doing wrong along the way, but when i put

require ‘digest/sha1’
class Emailer < ActionMailer::Base

the encryption didn’t work, however the same exact syntax when i put it
in my user model, worked;

require ‘digest/sha1’
class User < ActiveRecord::Base

i restarted the server, and am in development mode.
is there a deeper problem, or am i being blind to some stupid note?

many thanks,

harp