CodeCon 2006 notes

I went to CodeCon 2006, and I had a great time. Here are my rough, incomplete, unedited notes on the projects presented this year. Dan has also posted his notes. (If you’re interested, I also have notes from CodeCon 2005 and CodeCon 2004.)

Day 1

Day 1

Daylight Fraud Prevention (example)

Anti-Phishing prevention, tracking and detection through real-time web-based forensics.

wow he’s going fast. ok, catching up…

types of phishing:

  • impersonate (standard)
  • forward (mitm through http and post, more sophisticated)
  • popup (in front of real site; mostly deprecated)

current solutions are insufficient:

  • bounce email monitoring (since email headers are forged)
  • whack-a-mole on phishing hosts
  • detect known phishing email signatures (like virus scanners)
  • toolbars with host blacklits and heuristics (have to push updates)

basically like squid (server-side) for fraud prevention. single apache host w/modules. sniffs headers, compares referrers, etc.

has built-in phishing creation tools for testing!

imitate: doesn’t allow logins from non-whitelisted referrers looks for hijacked images, x’es them in red (or whatever) for visibility phishing emails are often html, so this can be done in the phishing email! cool.

forward: looks at login frequency, number of different logins, etc. from individual hosts and blacklists above threshold

does proxy detection through java, depends on clients having java configured incompletely, as is common by default

proactively prevents mirroring w/dynamic links and client monitoring interesting

  • can hide dynamic links, dynamic hijacked images, etc. as tracking images, e.g. for marketing.

very solid. i especially like putting this on the asp server, not on the client. this should come built into apache, or at least in an established apache distribution.

business case is tricky though. it perfectly complements schneier et al saying that this will only get fixed if companies and service providers are liable, not the consumer.

sane philosophy: no silver bullet, just lots of combined signals, weighted appropriately

lots can be automated. others have simple heuristics. others can be hard-coded (aim, mailing lists, etc.). others handled with data entry farms in china/india. some problems are hard for programs, easy for people. amusing cost/benefit analysis. :P


Pioneering Web safety by testing and rating every site, download, and form on the Internet.

honeypot for malware, spam, etc. except active, not passive

lots of attention to usability and accessibility!

browser extensions and pages that distill info down into single, analog red-yellow-green metric, etc

annotating search results (google etc) w/very simple red/yellow green icon, more info on popup

very cool since target audience is not extremely computer literate

crawling alone is interesting problem – which sites to focus on?

also combining factors and weights from different sources (apps, email, exploits, link analysis, popups) to evaluate single site(s)

client-side machine state monitoring, a la tripwire, isn’t exactly sexy, but very necessary. (watch for anything unexpected).

monitors site content and behavior over time, a la tripwire. if interesting things happen (e.g. server upgrade to version w/exploit), route for more in-depth monitoring.

working with grey-hat and white-hat security orgs to share info.

very cool, but adoption is going to be tough. target audience won’t know they need it, so they won’t get it. :/

video of spyware installing, fake anti-spyware installing through wmf exploit, windows ineffectually noticing spyware, etc. hilarious.

ppl in the audience worry that siteadvisor itself fits the conventional definition of spyware; it’s only distinguished by its intent. funny.

VidTorrent / Peers

A scalable real-time p2p streaming protocol.

basically multicast on top of bittorrent

related academic work (bullet, splitstream, etc.) don’t work in practice

bittorrent is opposite, evolved from what worked in the wild. only problem is it’s for files, not streams.

wrote “peers,” a platform/language for rapid development of p2p protocols. basically provides continuations for asynchronous rpc. currently has at least python bindings. seems like a smaller, less powerful version of p2…but still cool.

includes nat traversal and rendezvous support. they didn’t give its success percentage in the field though. :/

stream is chunked continuously that it can be carried by multiple nodes. nodes are organized into standard overlay network.

for live streams, how do nodes get the stream ahead of time? or do they not, and delay is variable?

a: they subscribe to stream source. takes advantage of asymmetric b/w of typical dsl or cable – need enough downstream b/w to receive full stream, but only need enough upstream to send partial stream (just its chunks)

tested with ns (but w/o failure injection). network visualization was fun

demo broke, couldn’t watch actual video…but a breakage means there’s at least real code, right? :P

trees are organized w/bandwidth and latency (rtt) probes. subscribers keep buffer per tree because tree needs all transmitting nodes

these guys knew their stuff wrt real-world p2p overlay networks, network distance and b/w / latency behavior, etc. very cool.


A popularity-based P2P file sharing system based on BitTorrent

slides and presenter seem a little basic. quotes like “basically a big C drive” and defining the word decentralized. he probably just way underestimated the audience. :P

starts off with lots and lots…and lots…of background:

  • % of web traffic by type (ftp, email, http, p2p) over history
  • defined p2p, decentralized, peer, etc. (!)
  • described napster (direct sharing, centralized index) and even client ui
  • mentioned keyword poisoning as drawback of index
  • explained bt’s chunking, lack of index, instead ad hoc web sites (suprnova)

provides a hierarchical, versioned filesystem of torrents. edits create new versions, and “popularity” of each version is measured w/individual user prefs. default view is most popular one.

ui is web-based, daemon runs on localhost (like gds)

e.g. comparing popularity of dir w/ or w/o a given file can measure popularity of that file

each version is implemented as a file distributed by bittorrent. fs itself is stored in kademlia. each user can store a pref for each dir; (ip, dir) pref is key, dir contents are value.

users are identified by IPs. what about NATs and proxies?!?

brad templeton asked, what prevents ppl from spamming the prefs and making their own stuff popular? thomas: nothing.

however, there are a number of existing approaches. one of my favorites is ed felten‘s ratings idea. soon disk and bandwidth will be effectively unlimited, so we could basically push all content to everyone. then the problem isn’t distribution, it’s vetting and rating the content to prevent poisoning.

i can’t find anything about this on his site, though…not even abstract. does anyone know of one?


An open-source behavioral malware analysis sandnet

skipped it. couldn’t take a third malware talk in a day.

evidently i skipped the wrong talk, though. friends said this was actually really good. lots of interesting, detailed info about how malware works, and also a fair amount about vm detection.

Day 2


Minimizing “interesting” files subject to a test of their interestingness.

many large systems and tools take large inputs (e.g. search engines, NLP, compilers). when the tool crashes on a large input, how do you isolate the part of the input that broke it?

define an “interesting” input as one that has the specific result – e.g. not just any error or crash, but the exact crash, stacktrace, core dump, etc. that you’re trying to fix.

can specify in a shell script

algorithm: for each granularity g from 0 to log(2) N partition the input into 2^g parts for each part is the input w/o the part still “interesting”? if so, dump that part

results in a “one minimal” input: removing any line would make the input not interesting!

my god. in the first five minutes, he’s presented a very very simple algorithm (and gave an example!) that solves a real problem.

dirt simple, very well explained, clear motivation, solution, and application! wow. very very impressive. brute force, but (and) it works!

more interesting. can you use this to find bugs that aren’t dependent on input, by selectively removing parts of code, until you end up w/just the broken code?

provide “interesting” test to delta as flex filter

concrete example: gcc choked on 250kloc codebase, delta reduced it to two pages!

“topformflat”: easy optimization for code. use really simple inherent structure, blocks defined by curly braces in c++, to pick parts to remove while maintaining syntactic integrity.

many applications if you can configure and present them to delta

e.g. instrumenting java binaries (e.g. jvm) – give delta config file w/all jars, delta reduced to just jars that induced failure

basically simulated annealing – large continuous subpsace, measurement of goodness, random local movement, and “temperature” for size of moves

it’s evolution! goodness == fitness function, random local moves == mutation, iteration == trying input w/o parts. “temperature” is new though.

delta: goodness == interestingness, random local moves == mutation, iteration reproduction

gcc people are very happy w/this, they use it to reduce most bug reports

so so so cool, mostly because a) it’s dirt simple and b) it works!

interesting q’s: extending topformflat for other langs/data types, how to use delta for runtime failures, best: delta-minimize input, then delta-minimize code to just part that exhibits bug!


Approximating Solutions to Nigh-Unsolvable Problems–Fast!

covered complexity theory and NP-completeness, etc. in a minute, max. heh.

explained local search over state space of possible solns, fitness fns, local minima/maxima, etc.

fitness fn must be:

  • cheap. ay, for np problems, how? seems like halting problem
  • comparable (sure, quantify based on e.g. time)

current approaches to local search:

  • hill climbing (dumb, simple)
  • annealing (random changes plus hill climbing)
  • genetic (annealing w/combining solutions, fitness fn has randomness)

well-prepared and practiced talk, good speaker, rehearsed jokes, plus physical comedy! other speaker literally acted out local search w/chairs and stools, pretended to be drunk for annealing, etc.

djinni isn’t any new algs, it’s a framework for applying local search algs to arbitrary problems

spent a long type talking about how the World, Solution, and Engine types are decoupled, as opposed to current state of the art. is that really such a big breakthrough?

spent more time explaining type-safety and compile time vs. runtime, runtime and compile time polymorphism (ie virtual methods vs. overloading)…why are they explaining this?!?

more good jokes about federal law, NP-completeness and travelling salesmanship vs. energy in the universe (“thermodynamics is such a downer”)

demo: got an approximate soln to 100-city TSP, within 1% of optimal, in tens of seconds. not bad.

still, it only finds instances of solutions, not algorithms. that makes this way way way less interesting. boo.

it’s “the first” open source implementation of the Ohlmann-Thomas Compressed Annealing algorithm (INFORM 2006)

aimed at embedded systems w/low executable size (48k) and memory req’ts (3 * sqrt of problem size)

not really my bag, but a friend who works in this area says he was impressed. he’s considering trying it out.


Open source push-to-talk videoconferencing and screen-sharing

remote collaboration tool a la groove. oriented toward 1-to-1, not groups. not based on red swoosh‘s p2p platform.

i know david (and mike, below) from the p2p-hackers. they both do great work. i’m already familiar w/iglance, based on the discussions david and i and others have had on p2p-hackers, so this will probably be short.

iglance uses lots of current tech – p2p, nat traversal, shared whiteboard / browser, video conferencing, voip, etc – but focuses on unifying them into a good user experience.

specifically, iglance attempts to integrate video into the overall experience

tries to replicate implicit real-world conversation mores:

  • don’t explicitly call someone, just start talking
  • don’t set away msg, just go
  • real-world privacy stuff: either both ppl can see each other or neither

also more natural twists on vnc-style screen and input sharing:

  • can share individual windows, not whole desktop
  • instead of fighting over single mouse pointer, each remote user has their

own pointer, visible to everyone, but only one has control at any time.

tries hard to integrate easily w/existing apps (sharing, pointing, etc)

i like this because david knows what he’s doing wrt the underlying tech, but he rightly see it as a means to an end, not an end in and of itself.

went on to mention specific “hot tech” – sip/simple, speex/theora, and specifically (udp) nat traversal. in a nutshell, he didn’t like stun, turn, and ice – more theory than practice – so he rolled his own. details in the p2p-hackers archives.


Anycast for Any Service

i know mike from p2p-hackers too. he’s the guy behind nyu’s coral.

presentation clearly reflects mike’s academic background. talk’s organization (motivation => related work => design => implementation => performance measurements => future work), citations, tone, etc.

oasis attempts to provide automated local mirror/replica selection (instead of making users choose mirror, a la sourceforge or used as next-gen backend for coral.

current solns:

  • probe all mirrors for bandwidth/latency product (expensive, gets stale fast)
  • define euclidean space (a la vivaldi and meridian), assign coordinates to hosts based on others (gets stale fast)

he didn’t come out and say so, but mike’s pretty down on coordinate systems for network distance in general. he uses them roughly in oasis, but with a healthy dose of skepticism :P

uses DNS frontend for resolver mechanics, oasis backend for actual local redirection smarts

two levels of locality:

  • client issues DNS req to oasis server, it redirects to nearby oasis server
  • client re-issues DNS req to nearby server, it resolves to nearby host

how to determine regions? ip addr isn’t good enough, too many are dynamic. instead, use prefix, specifically grouping by AS as defined by BGP.

map subnets to define regions based on network distance, then do search over given replicas by region to find closest

minimizing active probing is a big thing, so spread probe results (regions and specific node coordinates) through oasis core by epidemic gossipping instead of by active discovery

deployed on planetlab over ~300 hosts

discussed coral and opendht. sure. i knew they used oasis…

…but whoa. i hadn’t heard about ocala before. it’s intended to be an overlay network standard, deployed as an intermediary so that legacy transports (tcp, udp) and clients (ssh, irc, firefox) work w/o any changes on the client. very cool.

Query By Example

Data mining operations within PostgreSQL

this was a google summer of code project! chris lavoie mentored. yay.

motivation is pretty clear. querying and data mining is big business.

however, creating good unstructured keyword queries is hard.

  • synonyms (record, code, etc.)
  • syntactic ambiguity (newspaper headline: “Eye Drops Off Shelf”)
  • namespace collisions (apache: indian tribe, helicoptor, or web server?)

ranking is hard too. she even slams pagerank. aww… :P

clustering and clsasification are known problems w/known solns, as is adding new data to existing datasets’ clusters and classifications.

finding discriminant fns for clustering/classifying is dosable, but finding ones that handle new data well is very hard.

introduced support vector machines, gave background. whee.

all of this is already done and works well. query by example takes the existing clustering and classification stuff and provides a new interface to it, specifically SQL by example.

add “EXAMPLE KEY” option for WHERE and ORDER BY:

  • classical music:

    SELECT title FROM songs WHERE EXAMPLE KEY title LIKE (“Moonlight Sonata”, “Prelude in C# Minor”);

  • people by how close to your age they are

    SELECT name FROM people ORDER BY EXAMPLE KEY ((20 > 5), (22 > 50));

integration w/postgres was easy,

  • new syntax in parser
  • learning function in analyzer
  • leave optimizer as is
  • results engine in executor

unfortunately, it only works on numeric values so far. sigh. as jonathan noted, you can do those fairly well already w/ranges. most of the value is in the clustering on unstructured text fields. get that working!

demo was very effective. run a sql shell, connect to a postgres db, run a few WHERE and ORDER BY queries w/EXAMPLE KEY, and they worked as advertised. cool!

great application of well-understood research (ML) to real-world problems (sql dbs and data mining). not my bag, but i have to run ad-hoc reports over sql dbs at work way too often, so i know this is very applicable and timely.

…ok, meredith just wrapped up answering the questions and, holy shit, len just proposed to her. in front of the entire conference.


len’s proposal was short and sweet, but totally heartfelt. meredith said yes, of course, and everyone jumped up and gave them a standing ovation. that’s amazing. they were both overwhelmed, really emotional, and pretty much speechless. i’m even a little choked up. *sniff*!

congratulations, len and meredith!!!

Day 3

up until now, len had spent his remarks mostly on thanking sponsors, etc. this morning he took the stage and talked a little more. he first asked if people had had fun at the CCCP charity dinner (yes!) and at Nerd Salon at Annie’s Social Club (which I didn’t make it to :/). he went off on Annie’s Social Club, and rightfully so, since they double-booked Nerd Salon with a disruptive karaoke club, and the owner was really uncooperative.

they called the W hotel right then and asked if they could provide a venue on the spot, and surprisingly, they did. wow, props to the W.

he then talked about the history (him and bram and jonathan, nv, no starch press, etc.), the “good old days,” why this fits the community more than industry and academic conferences, and specifically the price and how they intend to keep it at the under $100 price point for obvious reasons.

and then the real final thanks to the volunteers, sponsors, organizers, etc…


A platform for writing dynamic voice menu systems, in Perl

standard motivation, recorded menus w/push-button interaction suck. he wants to write good IVRs (integrated voice responders?) based on asterisk.

for demo, ran asterisk on his laptop and connected a real phone. cool! had a canned IVR with long slow menus, and waiting to hear the option you wanted was frustrating. all too familiar. it hung often though. :/

dido lets you create menus dynamically, use text-to-speech (with festival), and reorder options based on popularity. even better, it can customize the orderings for each caller, identified by their phone number (w/caller id).

weird though. it doesn’t just present the number=>option mappings in a different order, it actually changes the mappings itself! strange, seems like bad usability. why?!?

asterisk’s current extentions.conf language is very very weak – runs external processes for loops and branching, all vars are global, etc. (brad templeton notes that mark, the asterisk developer (?), switched it out for a better language in the latest version.)

ok, so the motivation is crystal clear, the demo is cool, the code clearly works (since it breaks! :P) however…the talk wasn’t really organized at all, and he didn’t have slides! he tried to debug the demo while he talked (and trailed off often), didn’t give much background, jumped straight into implementation details, etc.

dido was understandable despite the lack of a complete demo or prepared talk, which speaks to the quality of the project itself.

however, this is just a band-aid on a machanism (IVRs) that really needs to be rethought from the ground up.


A free/open-source platform for online group deliberation and dialogue

i know ben and brendan from stanford undergrad and TAing, and todd and kieran know each other from the CMS community and the CHI conference in portland, so we got the low down on deme before their presentation.

we also heard the war stories of them staying up until 3 saturday night to finish the slides and check in code on major new features. ah, the fine tradition of preparing presentations and papers at the last minute. :P

some traditional group tasks (running meetings, making budgets, etc.), as well as deliberation online, really require in-person interaction.

as that gets harder, you see chilling effects on certain types of groups, dependence on locality, etc.

current solns (mailing lists, wikis, bulletin boards) are ok for communication, but not action. goal is to enable collaborative action.

provides basic stuff since it’s necessary: message boards, chat (ajax), file posting, etc.

new stuff is chat based on agendas, chat based on project planning, split-screen displays, flexible polls, threaded commenting in docs, etc.

attention to usability w/explicit affordances and multiple “views” on data.

demo showed groups, shared doc creation and commenting, meetings, decision making, announcements, and (whee) ajax chat.

ajax in other places – doc editing, polls. a few interesting javascript development tips and tricks, optimizing to browser-specific calls, and a pretty significant oo library for javascript.

looks very complicated and powerful, probably too much so for target audience of semi-computer-literate users. interface is so busy it’s overwhelming.

evolutionary in most parts, but lots of cool ideas. focus on group action is definitely unusual and worthwhile.


Unified access to system, service, and application configuration.

(Simon Law of Net Integration, backup presenter)

simplify and unify *nix service, app, and user config and settings.

deployed as a library that abstracts access to config files.

has backends that parse existing apps’ configs (/etc, dotfiles, properties files, etc.) and frontends that present configs in certain formats like gconf dbs.

internal implementation is key/value pairs organized hierarchically.

also supports notifications when configs change, access control, etc.

huge adoption hurdle, but a noble goal. :P

Remailer To Go

Disposable anonymous remailers

Len Sassaman and Miles ?

len is the penultimate cypherpunk. he maintains mixmaster, and he’s strongly interested in anonymous remailers and anonymity on the internet in general.

he wanted a bunch of small, self-contained computers w/a wifi radio that will automatically boot up mixmaster and advertise themselves as available remailers when they connect.

he’d leave them in coffee shops, near open home and corporate wireless access points, hell, on the side of buses and trucks so that when they stop next to an open wap.

miles took this and ran with it. he connected a cloth solar panel to a gumstick computer and a wireless card, determined the power req’ts (roughly two watts continuously), and hacked it all together. sooo amusing and fun.


Low stress, high functionality version control.

motivation: version control is necessary but can be horribly frustrating and incomprehensible.

monotone attempts to do version control w/o stress. most importantly, it’s understandable; you get what it’s doing under the covers.

universal identifier is hash of a file. the file might be an actual version of a file stored in monotone, a monotone manifest (repository metadata), a “revision” (a point in history, ie a change number, represented w/old and new manifests’ hashes), etc.

files are stored in trees, trees stored in manifests, revisions are DAG over manifests, increasing in time monotonically.

“certs” are key/value annotations on revisions. branches implemented as certs.

client workspaces are stored as single file with all file versions, manifests, revisions, etc., as well as full project history! standard argument is disk is cheap…which is true, but bandwidth isn’t!

hrm. they’re trying really hard to convince us that monotone is simple. fair enough, it is, i get it. :P they’ll stop right after explaining a design point and say that “anything you think you can do with this, you can do!” i bet, but i’d love to hear details!

ooh, they have a great algorithm for diffing forked repositories. represent repo as merkle trie, a tree of hashes. store leaves’ hash in their nodes, then parents’ hash is hash of concatenated childrens’ hashes.

to diff, start at two roots’ hashes. if equal, no more diffs in the subtree. if different, compare childrens’ hashes and recurse. when you get to leaves whose hashes differ, that file has a difference.

odd. they seem to think that they’re the first to allow synching to previous versions, and committing against previous versions. uh, subversion? perforce? most others?

meh. another codecon, another version control system. good talk at least.


An application stack enabling the rapid development of collaborative, Semantic-Web enabled applications.

basically a platform for making wiki servers. not individual wiki sites, but entire wiki server codebases.

sheesh. i know engineers like building platforms and infrastructure, not end-user apps…but this is taking it to an extreme.

python-based. uses rdf for storage, xslt for processing, xpath/xquery for querying. lots of built-in xpath tools. served on raccoon, an rdf-based server.

platform itself is web-based. has lots of internal reflection, query support, discoverability, etc. aimed at developers.

similarly, can even view and edit raw rdf (at your own risk).

also, webapp development – code, config, content – is done through web interface too.

showed rdf stored on file system in file browser – behind the scenes, whee!

frankly, it looks pretty conventional. it’s definitely modern…but not especially differentiated from all of the other wikis out there. :/

…it is necessary, though. every codecon has to have at least one wiki, version control, and security project. :P


A static-time whole-program dataflow analysis for C and C++

had to leave early, so i missed this one. boo!

3 thoughts on “CodeCon 2006 notes

  1. Yes, UniConf really is about solving a social problem through technological means, but we’re trying very hard to get adoption.

    And for the most part, we are slowly succeeding. It’s really about having code that solves a tedious problem, so that people can write code that solves interesting ones!

    Simon Law

  2. Very nice overview of CodeCon! Just a note of clarification on our project, Deme, however. I’m not sure what you mean when you say it is aimed at semi-computer-literate users. Deme is aimed at the level of users who already use web-based groupware, the effectiveness of which has been established in at least some of the grassroots groups we work with. Other aspects of the PIECE project address computer literacy and access. But Deme’s aim is to give people who are already pouring over bylaws, budgets, and grant proposals, and who use listservs and web survey tools, a new set of capabilities online. You could think of this as an application of Engelbart’s bootstrapping idea. Programs like Word and Photoshop are very complicated, especially the first time you see them, but have had a tremendous impact on low-resource communities like east palo alto as people have learned to use them. We often get the comment that people from underserved communities need simpler tools. Certainly one must be mindful of accessibility in design, and the comment from an audience member at CodeCon about font-sizes was a good illustration of that. But my experience so far is that people in east palo alto do not get overwhelmed by featureful software, and are just as good as more privileged users at learning them when there is a clear reason for doing so and when the UI is a solid design.

    Todd Davies

  3. hey todd! agreed, great points. i definitely didn’t mean to imply anything about the technical competence of underserved communities. i guess i was speaking more to the deme interface in general.

    for example, i’m a somewhat capable hacker… but other than that, in many ways, i’m only semi computer literate. i’m rudely reminded of this when i try to use many common web apps. similarly, deme’s interface looked so powerful and feature rich that it might overwhelm me.

    …of course, i haven’t used it in depth, so i don’t know for sure. if so, it’d probably be more a failing of mine than of deme’s. :P

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