Introduce a new page to the Account Wizard where user can select a cryptographic key to be set to the newly created identity. Use can also generate a new key pair or import an existing key from file.
The page follows the Personal Data page and is only shown when the Personal Data page is enabled.
I'm wondering if I should maybe move the "Always sign/always encrypt/never sign/...." combobox from the Personal Data page to the Crypto page, since it's crypto-related...?