To achieve this, you publish policies asserting that the client runtime must ensure message confidentiality and must provide evidence of the user's identity (user ID/password or a certificate).

Yet despite strong evidence, most people still do not know that alcohol increases risk of cancer, so it is clear we need to do more to get this message across.

The onus of proof requirement means that your organisation should establish a system whereby evidence of each recipient's consent for each commercial electronic message sent can be produced.