[web2py] using CRYPT in SQLFORM.factory doesn't work?

[niknok]

I tried:

    form=SQLFORM.factory(
        Field('card_number','string'
                ,label='Enter a card number to verify'
                ,requires=CRYPT(auth.settings.hmac_key))

But instead I found form.vars.card_number unencrypted.  This is on w2p
v1.94.5.

/r
Nik