Category Archives: P2P

daily links

· Bloglines API

· Paul Graham on what the Bubble got right: “… what would be wrong would be that how one presented oneself counted more than the quality of one’s ideas. That’s the problem with formality. Dressing up is not so much bad in itself. The problem is the receptor it binds to: dressing up is inevitably a substitute for good ideas. It is no coincidence that technically inept business types are known as ‘suits.'”

· LionShare: “… an innovative effort to facilitate legitimate file-sharing among individuals and educational institutions around the world.”

· .NET Reflector: allows you to view the source code to most .NET framework classes and code written in .NET. So how does one write / compile code in such a way as to not allow someone to disassemble their code?

Rendezvous and Java example

Lots of talk right now about Apple and it’s releasing of Rendezvous (Matt #1, Matt #2, Ted, Marc, Sam) into the wild. I downloaded the Windows Preview and extracted the SDK and was able to get minimally interesting things up and running very easily using Java. Below is a simple class that implements the BrowseListener interface and has utility methods for finding iTunes (protocol = DAAP), HTTP Servers (protocol = HTTP) and printers (protocol = LPR).

// class that implements the BrowseListenr interface
public class TestBrowseListener implements BrowseListener {
 DNSSDService myBrowser = null;
 public void serviceFound(DNSSDService browser, int flags, int ifIndex,
  String serviceName, String regType, String domain) {
  // do stuff when a service is found
  System.out.println("Service Found\n");

January P2P Journal links

Latest issue of P2P Journal is out, you can download the PDF here.

Remaindered links from the article:

Some Specific Projects in Collaborative Computing:

Peer To Peer Working Group, “Bidirectional Peer-to-Peer Communication with Interposing Firewalls and NATs”:

P2PWall – IPTables blocking of P2P traffic:

CTCP (Client To Client Protocol):

JOSE (stands for Java Open Source Exchange) is envisioned as a peer-to-peer network that allows developers to search, view and download source code made available by other peers:

New P2P applications and betas released:
· Skype
· Kappie

Neural Network Markup Language:

Notes on Peer-To-Peer: Harnessing the Power of Disruptive Technologies

Peer-To-Peer (amazon, oreilly) is an old book by internet standards (published in March of 2001), but chock full of interesting thoughts and perspectives.

· On gnutella, did you know that you can watch what other people are searching for? The book has a screenshot of gnutella client v0.56, I have Gnucleus, but you can do it in Gnucleus by clicking Tools –> Statistics –> Log. Betcha you didn’t know that an entire company was founded based on that idea did you?

· footnote: Chaffing and Winnowing: Confidentiality without Encryption by Ronald L. Rivest

· On the ‘small-world’ model and the importance of bridges: “.. The key to understanding the result lies in the distribution of links within social networks. In any social grouping, some acquaintances will be relatively isolated and contribute few new contacts, whereas otherws will have more wide-ranging connections and be able to serve as bridges between far-flung social clusters. These bridging vertices play a critical role in bringing the network closer together… It turns out that the presence of even a small number of bridges can dramatically reduce the lengths of paths in a graph, …” — Reference “Collective dynamics of ‘small-world’ networks” published in Nature, download the PDF.

· Publius looks like some cool software

· Crowds: “Crowds is a system whose goals are similar to that of mix networks but whose implementation is quite different. Crowds is based on that idea that people can be anonymous when they blend into a crowd. As with mix networks, Crowds users need not trust a single third party in order to maintain their anonymity. A crowd consists of a group of web surfers all running the Crowds software. When one crowd member makes a URL request, the Crowds software on the corresponding computer randomly chooses between retrieving the requested document or forwarding the request to a randomly selected member of the crowd…. ” — Read more about Crowds at the official site.

· Tragedy of the Commons. This idea was mentioned in chapter 16 on Accountability and is talked about in various other books I’ve read, but I’m not sure that I ever recorded the source. The idea came from Garrett Hardin in a paper written in 1968 called “The Tragedy of the Commons”, which you can read on his site.

· On accountability and how we really *are* all just six degrees apart. Read the PGP Web of Trust statistics if you don’t believe it.

· On reputation systems, specifically Advogato’s Trust Metric

· On reputation scoring systems, a good system “… will possess many of the following qualities:

  • Accurate for long-term performance: The system reflects the confidence (the likelihood of accuracy) of a given score. It can also distinguish between a new entity of unknown quality and an entity with bad long-term performance.
  • Weighted toward current behavior: The system recognizes and reflects recent trends in entity performance. For instance, an entity that has behaved well for a long time but suddenly goes downhill is quickly recognized and no longer trusted.
  • Efficient: It is convenient if the system can recalculate a score quickly. Calculations that can be performed incrementally are important.
  • Robust against attacks: The system should resist attempts of any entity or entities to influence scores other than by being more honest or having higher quality.
  • Amenable to statistical evaluation: It should be easy to find outliers and other factors that can make the system rate scores differently.
  • Private: No one should be able to learn how a given rater rated an entity except the rater himself.
  • Smooth: Adding any single rating or small number of ratings doesn’t jar the score much.
  • Understandable: It should be easy to explanin to people who use these scores what they mean — not only so they know how the system works, but so they can evaluate for themselves what the score implies.
  • Verifiable: A score under dispute can be supported with data.”

· On reputation scoring systems: “Vulnerabilities from overly simple scoring systems are not limited to “toy” systems like Instant Messenger. Indeed, eBay suffers from a similar problem. In eBay, the reputation score for an individual is a linear combination of good and bad ratings, one for each transaction. Thus, a vendor who has performed dozens of transactions and cheats on only 1 out of every 4 customers will have a steadily rising reputation, whereas a vendor who is completely honest but has done only 10 transactions will be displayed as less reputable. As we have seen, a vendor could make a good profit (and build a strong reputation!) by being honest for several small transactions and then being dishonest for a single large transaction.

· The book was written when Reputation Technologies was still a distinct company, but I thought this list of Reputation and Asset Management vendors was interesting in that reputation is something that is becoming more and more important.. for instance, when was the last time you purchased something from eBay where the vendor had a bad rating? Never right? Did you ever stop to think about how the vendor in question got a bad rating? Since when is eBay a good judge of someone’s character? Why do we trust eBay’s reputation algorigthms?

· On the optimal size of an organization: “Business theorists have observed that the ability to communicate broadly and deeply through the Internet as low cost is driving a process whereby large businesses break up into a more competitive system of smaller component companies. They call this process ‘deconstruction.’ This process is an example of Coase’s Law, which states that other things being equal, the cost of a transaction — negotiating, paying, dealing with errors or fraud — between firms determines the optimal size of the firm. When business transactions between firms are expensive, it’s more economical to have larger firms, even though larger firms are considered less efficient because they are slower to make decisions. When transactions are cheaper, small firms can replace the larger integrated entity.

· “Why Johnny Can’t Encrypt: A Usability Evaluation of PGP 5.0 (pdf)” from Alma Whitten

JXTA update from James Todd

James Todd, who works on the JXTA engineering team at Sun, blogged about the JXTA roundtable held just recently in San Francisco. Some interesting projects are going on in the JXTA community:

P2PSockets: “The Peer-to-Peer Sockets Project reimplements Java’s standard Socket, ServerSocket, and InetAddress classes to work on a peer-to-peer network rather than on the standard TCP/IP network.” — This project is especially interesting in light of the things that Verisign is doing. P2PSockets could potentially be used to create an alternative peer-to-peer domain name system (which would probably have a host of it’s own problems.)

Paperairplane: “… a Mozilla plugin that empowers people to easily create collaborative communities without setting up servers or spending money. It does this by integrating a web server into the browser itself, including tools to create collaborative online communities that are stored on the machine. Web sites are stored locally on a user’s machine. A peer-to-peer network is created between all of the Paper Airplane nodes that are running in order to resolve domain names, reach normally unreachable peers due to firewalls or NAT devices, and to replicate content.

JNGI [pdf]: “The JNGI project is a framework for distributing applications among JXTA peer groups by implementing a classic Worker/Task pattern.