I hadn't previously looked at lattice crypto in much detail, and was not aware the keys were as big as they are; thanks for pointing that out. That said, a big

I hadn't previously looked at lattice crypto in much detail, and was not aware the keys were as big as they are; thanks for pointing that out. That said, a big performance hit isn't necessarily the same thing as being practically unusable. It certainly explains why nobody's using it now. I'd be curious to read some concrete performance analyses. A sibling comment points out one use case for symmetric-only crypto. I'm also curious what people would actually do if forced to deal with a symmetric-only world. I think it is more likely that we'd see cumbersome ways of dealing with key distribution than that people would just stop using crypto in all the places we rely on public key schemes today. Think symmetric keys printed on your bank statement (maybe with a qr code?) We'd definitely see it used a lot less than now. That said, we'd probably have about the same number of people doing end to end email encryption; key distribution with an asymmetric scheme is no picnic either :P.