In the general case, repudiation is desired by users, and non-repudiation is needed in only very particular cases. Companies serving nontechnical users should m

In the general case, repudiation is desired by users, and non-repudiation is needed in only very particular cases. Companies serving nontechnical users should make repudiation the default, because if given the choice most users would prefer it to be the default. In the particular case of Google releasing its DKIM keys, I think I would need more context. What kind of repudiation property do users expect when sending emails over GMail? Is non-repudiability currently used by users for legal or business purposes? Probably the way to do it would be to announce a particular date maybe a year into the future that the private keys would be released.