my guess would be to just delete all local data, instruct the user to destroy all private keys, and consider the data delete it. I think in this situation, best

my guess would be to just delete all local data, instruct the user to destroy all private keys, and consider the data delete it. I think in this situation, best effort to "delete" the data is all you can do. IN this case, if all keys are deleted, the data effectively becomes meaningless bits.