Dining with the Cryptographer: A crypto road trip By Jim McCoy and Douglas Barnes "Hey Doug," said Jim. "You'll never guess who just called." Ever since Jim got mail from Chaum asking for his phone number (he doesn't have one), he'd been pretty anxious, spastically cramming old Eurocrypt proceedings and coming up with even more baroque crypto applications than usual. (We'll have a digicash auction for CPU cyles...) Finally they must have touched base while he was at work. "Let me guess", I ventured, "a call from Amsterdam?" "Uh, no from Dallas. Chaum wants us to go have dinner with him." "Dallas? What's he doing in Dallas?" "I think some conference or something." It was 4:30 in the afternoon; Dallas is a highly optimistic three and a half hours away. "Does he realize where Austin is?", I replied incredulously. "I think so... we're supposed to meet him at 8..." "Uh-hunh... right." Time to find a car. Frantic phone calls, beggings of coworkers. No question but this was not an opportunity to miss. Sort of like a Roman Catholic getting a call from the Pope. Finally get ahold of my wife, who has the only working car in the family. "You're going where?" she asked. "Dallas." "Dallas?" "Yep. Gonna meet David Chaum." "How does he know about you?" "Beats me. Actually, I think it's just Jim he wants, I'm along for the ride." Rush hour (such as it is) in Austin, pick up Jim, gas up, get munchies and caffeine for the trip. Hot topics in the car on the way up: "Where in hell did he hear about you?" "Is this Waco yet?" "Do you have any idea what he looks like?" "Wow, you really shouldn't be driving ninety..." "Did you have _any_ concept of where Dallas was when you agreed to this?" Since neither of us had ever really been to Dallas as an actual destination, we bought a map in Troy. (Home of the fighting Trojans.) Jim spent the rest of the way to Dallas (several hours) attempting to unfold the map. "What was that address again?", I would ask. "North Dallas Parkway." "Are you sure?", I would ask. "Yeah..." <time would pass, more folding and unfolding of the map> "Found it yet?" ... [Jim asks at this point that we mention there _is no_ North Dallas Parkway on the map; it's a frontage road.] We reach Dallas, a giant mass of undifferentiated suburban cancer cells on the north Texas plains. We still don't know where the hotel is, so we pull off at a random exit and up to a phone at a Texaco. Jim goes to the phone, just as we notice an extremely loud and violent confrontation between a customer and the clerk. Many folks sort of hanging around, gold chains, nice cars, tinted glass, everyone real tense. I realize immediately that we are the only white people in sight, and that the confrontation is getting louder. I bravely lock the doors while Jim makes the call. Blows are exchanged at the pumps as we pull away... After this things are a snap, we arive at the Grand Frobnintsky Hotel and meet Chaum. I'm expecting a short, balding Dutchman, he turns out to be a tall hippie from California, a taller, older edition of Eric Hughes. We are an hour and a half late, but he seems unperturbed, even a little stunned when I explain the distance in terms of European geography (dropping by Amsterdam from, say, Frankfurt or Paris). And off we go for food. Chaum had actually been here before (long ago) but we hadn't. We drove around in circles, three of the most indecisive humans on the planet, clearly waiting for the NSA to tell us where they were springing for dinner. We try one restaurant which (thankfully) was closing, and they gave us directions to Mi Piazo, based on our: "Um, we think it's, like, an Italian restaurant, Mia something or other..." Now, unbeknownst to Jim or I, we were _savagely_ underdressed for what turned out to be the best Italian restaurant in Texas. Chaum, at least, was wearing a jacket -- we looked our usual Austin slacker selves, having literally dropped everything and dashed out of our respective workplaces. Fortunately it was football night for the Dallas Cowboys, and the place was pretty much deserted. [Note: We started with a delightful cold antipasto, I had the seafood fettucini, Jim had lobster and crab ravioli in a mushroom wine sauce, and Chaum had something else... we remember what we had because, frankly, it was the best food we'd had in, oh, a decade or two.] He had come to Dallas not for a convention, but rather to work with a company that is implementing his smartcard technology for automated toll collection equipment. "It's hard to do this protocol in such a narrow window, but we're getting there. If the car is doing 60, there just isn't much time." Jim asked about what was motivating the company to pursue this secure, untraceable mechanism; Chaum believes that more and more people are increasingly aware of privacy issues and are more sensitive than ever about the data that is collected about them. "This company sees it as a major selling point... they want to be ahead in the technology over the others in the market, and they're willing to pay to do it right." Of course, we couldn't escape the mandatory conversation about our favorite son, Lawrence Detweiler of Colorado. Chaum was vastly amused by the whole saga, and we discussed some of the practical aspects of instituting is-a-person credentials and credential mechanisms in general. "Why don't you guys just go ahead and set something like that up," he suggested, "so you can shut him up." I pointed out that this had been suggested, but that LD was simply incapable of distinguishing the separate roles of keyservers and credential mechanisms. We resolved that even though it would probably have no appreciable impact on someone as far gone as Larry, it was something we should pursue. At our prompting, Chaum described the overall activities of his company. "There are three basic groups, one working on smartcards, one on software-only implementations, and another on electronic wallets." Basically, the smartcards are a fairly standard microcontroller with most of the i/o stripped out and their own software burned into ROM. The electronic wallets are more sophisticated consumer electronics for managing smartcards. He asked about our activities, and we told him about our recent work on secure telnet with Diffie-Hellman, and our Credit Union plans [which is how he heard about us]. From our point of view, after many meetings and telephone discussions with regulators, the regulatory environment seems like the easy part, with the software looming as a major hurdle for two people with about three and a half jobs between them. From Chaum's point of view, the software is the easy part, and he was delighted to hear how absurdly easy it is from a regulatory standpoint to start and operate a Credit Union. We discussed some of the non-anonymous, traceable proposals that have been presented; I asked whether the various attempts to come up with alternatives to his protocols were because a) they didn't want to pay licensing fees, b) they didn't know about digicash, or c) they _wanted_ traceability. His feeling was that most people had started working on this without examining work in the field, having only a background with public key cryptography, and had wedded themselves early on to their own, rather shallowly conceived protocols that are generally either too complicated or critcally flawed with respect to untraceability. He also acknowledged that some people and organizations did, in fact, seek traceability, but that this position would prove untenable in the face of consumer demand. Returning to the Digital Credit Union idea, we discussed ways in which we might collaborate on this venture. He was clearly very well disposed to the idea, and barring problems with export/import restrictions (the Netherlands apparently have odd export regs of their own) felt that we could incorporate some of the Digicash, Inc., software that is just now reaching the beta test stage. "And if we can't export it, we'll just send someone over here to rewrite it... end up with better code that way anyhow." The surly waiters were beginning to give us the eye, as it was pushing midnight; Chaum was starting to fade as well, still jet-lagged and clearly worn out from a whole day of meetings and somnolent from a huge dinner... so we jumped him and stole his wallet to give an example of the dangers of untraceable cash. Okay, maybe not, but Jim did ask him in this weak moment if he had any objections to people implementing public domain blind signature code along the lines of RSAREF. He thought this was a terrific idea, and enthusiastically approved. I asked some probing questions about what kind of software they would have available; he offered to forward a writeup of the various projects that are almost completed. We adjourned to the cocktail lounge at the Grand Frobnintsky Hotel, where, sipping cappuccino beneath a giant snowman made of marshmallows, we chatted some more, until Chaum appeared on the verge of falling into his steamed milk. After goodbyes, we parted ways. Halfway to the car, as if on cue, Jim and I just completely lost it and started laughing hysterically. All the tension and nervous energy of our mad dash to Dallas and meeting a hero of the digital revolution had melted away, and the full realization of the incredible experience hit us full force -- out of the blue, this guy whose papers we had passed back and forth and argued about endlessly over bagels, had called Jim up, invited us out to dinner two hundred miles away, we had a great talk, this incredible food, put new life into the Digial Credit Union project... and only about eight hours had gone by. The drive back was fairly uneventful; I started to nod after a bit and Jim took over the driving (which was a good thing, as I was both falling asleep _and_ stuck in the groove of driving about ninety). So, reenergized and still contemplating the wonderful food at Mi Piazo, we prepare to forge ahead... -- Jim McCoy (mccoy@binky.cc.utexas.edu) Douglas Barnes (cman@io.com)