1. Copyright, 1995-2004 1 Issues from Internet Technologies 2 – Apps for Collaboration & Subversion Roger Clarke, Xamax Consultancy, Canberra Visiting Prof/Fellow, Unis of N.S.W., Hong Kong, A.N.U. http://www.anu.edu.au/people/Roger.Clarke/........ II/CCCS-2-ACS.ppt UofQ CCCS, 6 December 2004

2. Copyright, 1995-2004 2 Apps for Collaboration & Subversion Agenda From Master-Slave to Client-Server From Client-Server to Peer-to-Peer Proxy-Servers, incl. Nymity Open Source and Open Content

3. Copyright, 1995-2004 3 Star Topology / Master-Slave Architecture 1950s Onwards

4. Copyright, 1995-2004 4 Client-Server Architecture 1970s Onwards Intra-Organisational

5. Copyright, 1995-2004 5 Client-Server Architecture 1980s Onwards Internet-Mediated

6. Copyright, 1995-2004 6 Multiply-Connected Topology / P2P Architecture 1970s but esp. 1990s Onwards Internet-Mediated

7. Copyright, 1995-2004 7 The Essential Nature of P2P In principle, Any Device is a client and/or a server In practice, Many Devices perform server-functions Collaboration inherent to the software Clients can find Servers Single Points-of-Failure, Bottlenecks / Chokepoints are avoided by means of networking dynamics Enough Devices with Enough Resources participate as Servers for discovery, and as Servers for services 'Free-Riding' / 'Over-Grazing' of the 'Commons' is restrained through software and psych. features

8. Copyright, 1995-2004 8 Why P2P Is Attractive Much-reduced Dependence on individual devices and sub-networks (no central servers) Improved Resilience (inbuilt redundancy) Much-improved Scalability (proportionality) Much-improved ability to service highly- peaked demand (more devices on the demand-side represent more server- resources) resistance to denial of service (DDOS) attacks (no central servers)

9. Copyright, 1995-2004 9 Issues in P2P Vulnerability to masquerade, pollution attacks (decoys) Unpredictability of, and Volatility in, the locations of processing services and digital objects Lack of Central Control, hence challenges to the imposition of authority, reduction in accountability Security Challenges, esp. embedded malware Surreptitious Enlistment of Devices (at least potential) Reticulation of Digital Objects in breach of the wishes of copyright-owners, governments, and individuals

10. Copyright, 1995-2004 10 Internet Nodes at Work

11. Copyright, 1995-2004 11 Proxy-Servers A intermediating node that performs functions on behalf of the sending and/or receiving node Proxies can filter content, or substitute content A nymous proxy passes on a substitute IP-address and perhaps identifiers and even data A nym is: Anonymous if unbreakable Pseudonymous if the link can be discovered

12. Copyright, 1995-2004 12 Closed, Lock in Software Copyright Licences with very restrictive terms re reproduction, adaptation, re- distribution Source-Code is commonly not provided The objective of the copyright owner is to maximise revenue, by imposing constraints on both competitors and customers Such software is generally very expensive

13. Copyright, 1995-2004 13 Open Source Software = Liberal Licence Terms The rationale is to enable cumulative improvements and enhancement, by exposing the source-code to more eyes The Free Software movement, since 1982: Richard Stallman and Comrades – http://www.fsf.org/ free as in speech, not free as in beer copyleft, so that derivatives are free too The Open Source Initiative, since 1998 Eric Raymond and Friends – http://www.opensource.org/

14. Copyright, 1995-2004 14 Open Source Software – Licence Terms Ready Availability of: a licence executable code and source-code Licence Permissions to: run the executable reproduce both executable and source re-distribute both executable and source adapt the source distribute adapted executables and source distribute within larger software packages Licence Constraints to: ensure that redistribution is no less liberal prevent subversion of the objectives

15. Copyright, 1995-2004 15 Open Content = Liberal Licence Terms What It Is Content available under liberal licensing terms, and without technological protections Motivations to enable access e.g. shared Learning-and-Teaching Materials to encourage improvements and enhancement by exposing the content to more eyes e.g. Wikipedia