Validation on password attr_accessor

I am using the authentication example of Rails Recipes book (around
page 135)

I am trying to make a sign-up form for it

I have the following method

def password=(pass)
salt=[Array.new(6){rand(256).chr}.join].pack(“m”).chomp
self.password_salt, self.password_hash = salt,
Digest::SHA256.hexdigest(pass + salt)
end

which seems to work

I use

attr_accessor :password

So that I can have a password field on my form

But if I use validates_length_of :password, :within => 5…40

The password always fails the validation even if I enter more that 5
chars etc…

Any help would be appreciatted

Thanks

Richard
Japan