What are the tradeoffs, assuming an email encryption scheme based on self custodied private keys and publicly published public keys? I don’t see any major disadvantages to using blockchain for this, and significant advantages. It’s a big deal if no one can selectively remove/conceal previously published info. If associating a key with an email, and someone is trying to impersonate you, you’ll know it, it’s not going to be hidden from you and specifically shown to someone else. It just makes sense to do it that way. Yes, you have to trust something at some point, but this is a way to minimize how much trust you have to give.