Just speculating here, but it might be possible to leverage the hash rate and messages passed via Bitcoin’s blockchain for security.

Think something like OpenTimestamps. One idea could be that you set up a firewall that requires an extremely high proof of work before accepting packets. The firewall might be some specialized hardware for this.

If your message was passed inside a block you could use the PoW from that? The idea is to set the bar prohibitively high and the bar doesn’t get higher than the PoW applied to bitcoin.

Again just speculating. I imagine if the guy had a novel idea he wouldn’t divulge the advantage publicly… 

 Or you can use signal or simpleX. 

We already have strong cryptography. No need to add pow to messaging. POW is just how we determine who gets to update the ledger. 

 Cryptography doesn’t prove the sender expended energy.

You can require the message be encrypted but the sender could’ve sent 100M emails. If your service requires PoW then it prevents a denial of service. You can also require requests to be collateralized with bitcoin so that the attacker needs to think twice. If they send to a honeypot they lost their corn and got nothing in return.

Forcing the messages to touch the chain severely restricts the volume of requests and also leaves a public audit trail. Again I’m just speculating here and honestly don’t have a clue what he’s trying to do but there might be something there.