Copyright, 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. II/CCCS-2-ACS.ppt UofQ CCCS, 6 December 2004
Copyright, 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
Copyright, Star Topology / Master-Slave Architecture 1950s Onwards
Copyright, Client-Server Architecture 1970s Onwards Intra-Organisational
Copyright, Client-Server Architecture 1980s Onwards Internet-Mediated
Copyright, Multiply-Connected Topology / P2P Architecture 1970s but esp. 1990s Onwards Internet-Mediated
Copyright, 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
Copyright, 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)
Copyright, 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
Copyright, Internet Nodes at Work
Copyright, 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
Copyright, 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
Copyright, 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 – 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 –
Copyright, 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
Copyright, 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