Required Signed Fields The following signed fields are required in all Secure Acceptance requests: ■ access_key ■ amount ■ currency ■ locale ■ payment_method ■ profile_id ■ reference_number ■ signed_date_time ■ signed_field_names ■ transaction_type ■ transaction_uuid ■ unsigned_field_names For descriptions of signed request fields, see API Fields.