[Cryptography] Business opportunities in crypto

[Jerry Leichter]

> 2. Privacy-preserving ad bidding. A bipartisan committee
> of Congress has recently raised this issue as a national
> security concern. Surely, after years of research, someone
> in the crypto community has come up with protocols that
> both protect bidders from one another, as well as protect
> the privacy of the intended 'victim' of the ad from all
> of the bidders (including the winning bidder).
Apple claims to do something like this in their (rather small) ad network.  But what exactly Apple provides, and how that aligns with what one might want, are not easy questions to answer.

> 3. Better stock market trading mechanisms. Currently, if
> you put in a 'buy' or 'sell' order, your own broker can
> 'front-run' you (hello Robinhood!) and offer an epsilon
> better bid than you, so you as a customer will only get
> your transaction done after all of the front-runners
> have been satisfied. Surely, there is a crypto protocol
> that won't reveal anything about your order until *after*
> it has been executed, so that front-running can no longer
> happen, and won't reveal anything about losing bids at
> all (because they may be good-til-cancelled orders, which
> want to remain in the queue for future bidding).
Maybe there's a protocol ... it's not clear, since in some situations you opponent is actually the guy you are trying to trade with, and you can't do a blind commitment without first agreeing on a price ... but is there one that's implementable efficiently enough to match the sub-millisecond times on which markets run these days?  The requirements here get really interesting.  Some friends, many many years back, worked on a system to distribute bids to multiple potential traders on an Ethernet.  They had to deal with being able to show that  the maximum time delay between when the first trader received the bid and when the last one received it was no more the x ms - where x was small enough to be really challenging, especially on a medium, like Ethernet, subject to random delays.
                                                        -- Jerry