A P2P Content Delivery System for Alternative Business Models Harnessing Internet’s Full Potential

H. Castro A. P. Alves INESC Porto, INESC Porto, Faculdade de Engenharia da Universidade do Porto Faculdade de Engenharia da Universidade do Porto Porto, Portugal Porto, Portugal

Abstract— The production, distribution and consumption of being commercially employed. Still, this embrace has been information goods have evolved through continuous timid and conservative, as CDists have generally only disruptions. Presently, these activities are being disrupted by transposed “Brick-and-Mortar” operating modes onto their the Internet and digital technology revolutions, which on-line operation. Illustrative examples will be presented in challenge established practices. P2P content diffusion is the following section. playing a key role in this process. This technology has In this work, we expose the state of the art of P2P frequently been regarded as intrinsically “ill-purposed”, but exploitation for content delivery and the problems it faces. this view is changing and it has begun to see some commercial We identify the root causes of such problems and infer a set use, even if timid and fraught with obstacles. In this article, we of techno-economic guidelines to be employed for on-line analyze the present use of P2P technologies in content media delivery success. We then lay forth the definition of a diffusion. Based on previously developed work, we identify the economic root of the present problems and discuss possible content delivery P2P system that appropriately complies with solutions. Finally, we describe a possible P2P architecture, the later guidelines. currently being implemented, that could be used to support the II. P2P MEDIA DELIVERY STATE alternative business models needed to fully exploit Internet’s potential and deliver content to the users in friendly way. Napster was the most notorious early case of an initiative of this kind. It was a hybrid P2P system [2] where content Keywords-component; P2P Content Delivery, Distributed listing and discovery services were centralized but its Network, Paradigm Change, Business Model, Free Content distribution was P2P. Its central provisions were legally Access, Lateral Gain Extraction, Digital Rights Management, targeted for copyright infringement aiding and it was finally Internet shutdown in 2002. Napster was subsequently followed by other, more I. INTRODUCTION decentralized, systems, such as Gnutella. This employed a Throughout time, the production-distribution- completely distributed operation mode that is far harder to consumption of information goods (IGs), and their legally target. Such fully distributed systems presented some associated socio-economic systems, have endured numerous problems regarding efficiency and reliability, so the next step changes. The greatest such changes, supplanting those in P2P evolution was the reintroduction of centralization in caused by the invention of the printing press, are the ones some of these system’s (such as FastTrack’s) services resulting from the appearance of the Internet. This through the employment of so-called super-peers to handle innovation, and associated technologies are shaking the data discovery and system coordination tasks [2]. centuries-old edifice of media production and consumption. Simultaneously, these same issues, also spurred the Their impact derives from the costless data reproduction, development of structured P2P systems which employ a nearly costless data exchange and disintermediation of the distributed, but universal, algorithm for the permanent consumer-creator relationship that they enable [6]. mapping of resources to peers in order to facilitate their P2P computer interaction follows this logical footstep, as accommodation and retrieval. The most relevant of such it optimally takes advantage of the offered cost reduction algorithms are CAN [15], Chord [16], Tapestry [17] and potentials, and vastly disintermediates the consumer-artist Kademlia [18]. A relatively more recent development has and inter-consumer interactions. Naturally, the use of this been the BitTorrent [5], system, which employs a bartering technology has seen an explosive growth, which, given its scheme to counter one of P2P’s older problems, free riding. low start-up costs, occurred primarily in the non-commercial The establishing of bartering, again, was enabled through the sector, frequently in the facilitation of copyright infringing reintroduction of some operational centralization (the activities. Established actors have had difficulties in dealing BitTorrent trackers) for the facilitation of sharing peers’ with this process. After considerable initial resistance, (not rendezvous. yet entirely abandoned), content distributors (CDists) have Presently, systems of all the described types (and other begun to embrace the Internet medium for IG delivery. Even mixed types) and generations coexist and interoperate in the more recently, P2P content delivery has also commenced Internet, and are frequently connected to the unauthorized exchange of copyrighted content between final consumers. This process has been accompanied by an also continuous the adoption of these new tools has, nonetheless, been legal and technical targeting of such systems by the content frequently marred by failure. production industry. For such reasons, P2P technologies have been looked B. Develpoment upon with suspicion, by CDists, from the start. Still, that As demonstrated, several commercial initiatives attitude has begun to change, for instance: Veoh [14], was an attempting to employ an on-line P2P approach, have Internet TV service which employed P2P technology (among appeared. They have frequently employed already existing, other means), for the diffusion of unprotected commercial and sometimes unreliable, P2P content distribution structures and user generated content. It searched for years for a for the delivery of their content (e.g. Qtrax and iMesh). More successful Business Model (BM) but ultimately failed in importantly, they have also frequently employed BMs which 2010; Babelgum [3], and Joost [8], are both Internet TV impose a restrictive content access policy (subscription, pay- services with an advertising based BM. Originally both per-view, etc), and used DRM enforcement schemes whose systems employed P2P streaming technology, but have operation is in-line with such BMs. The initiatives in scope eventually dropped it in favour of a client-server operation; have frequently, either failed (e.g. Veoh or ReelTime), or, in PPLive [12], is a P2P Internet video streaming service spite of the proven advantages of P2P, have abandoned this offering un-encoded content under an add-supported BM; delivery mode for a more traditional, and costly, client-server ReelTime was a video-on-demand provider that delivered one (e.g. Joost or Babelgum). some of its content under encryption and through a This trend of technological retreat has been caused by proprietary P2P technology. It employed a subscription and CDists hesitation between a complete embrace of a new pay-per-view BM. It has ceased to operate; Qtrax [13], techno-economical operation mode and the attempt to supplies a legal P2P music delivery service built upon the preserve legacy ones. This techno-economical Gnutella network. In time it has moved to a strictly conservativeness means that in most of these initiatives the advertisement based BM from a previous two tiered BM, employed BMs were based on content access restriction, and which also employed subscription revenue capture; Qtrax that the P2P delivery mode, with the inevitable loss of employs Digital Rights Management (DRM) technology to control over content it implies, is so frequently abandoned. enforce advertisement consumption; iMesh [7] is a media C. Conclusion content delivery system and an online social network which employs a Gnutella based centralized P2P strategy for The causes of the panorama, laid down in section III, content distribution. Its BM allows free access to some (lack of commercial success and technical regression), are content but relies on the permanent purchase or on the paid related to, as argued in [6], the non-observation or non- subscription to other content. acceptance, by the CDists, that the Internet medium has The employment of P2P content distribution technologies come to radically alter the technical, economic and social in the commercial sector is, thus, still in an immature phase premises that underline the universe of IGs production, but it is gaining momentum. Other examples, of P2P content distribution and consumption. This new medium virtually delivery employment, exist also in more research oriented eliminates storage, reproduction and distribution costs, and areas. One such notable case is the AXMEDIS project [19]. enables the disintermediation of the artist-consumer relationship. Its establishment represents the rise of a new III. ANALYSIS OF P2P SITUATION technical paradigm in the field of information exchange and manipulation [6]. A. Introduction During the “Brick-and-Mortar era”, CDists operated and In face of what was explained in section II, it becomes controlled the information content distribution structure clear that the non-commercial employment of P2P (stores, CDs, DVDs, etc). This structure was both socially technologies has been considerably steadier and more useful and inescapable, as it mediated the predominant successful than its commercial counterpart. The demands interaction between consumers and artists, (acquisition of placed upon these two types of systems are different, but the IGs). It was the scarcity and controllability, inherent to the success of the “free” P2P systems, pirate or not, reveals that materiality of the distribution structure that secured a useful this technology is technically sound for a variety of uses. role for CDists’, and assured their profits, on intellectual Further attesting this is the fact that during the entire process property. The Internet comes to eliminate the need for such a of P2P network evolution up to the present moment, these material structure as it constitutes a far more cost effective networks had an intense technical (DRM technologies alternative. That economic superiority stems from the employment and poisoning [9] of P2P networks), and legal automaticity and immateriality associated with that medium. assault waged upon them by the content industry and still, These characteristics of it, and their effects, are rendering the their proliferation was unabated [11], [4]. This reality traditional role of CDists’, useless. demonstrates that the strategy originally employed [6], by CDists’, thus, find themselves in a situation where the established content producers in their combat of what immobility leads to obsolescence, and progress (adoption of they considered to be piracy and to P2P networks, has failed on-line operation) threatens age-old reliable BMs [6]. [6]. As a result of that failure, even if reluctantly, those Conscious that immobility is unsustainable, CDists are entities have begun to use the P2P technology and Internet as attempting to go in the progressive way, but with a a content delivery platform in more innovative ways. Still, regressive mindset. This means that most CDists that pursue an on-line (even P2P), operational alternative, attempt to do freed from the burden of restrictively controlling access to so while preserving the economic status quo, inherited from their delivered IGs, they may then harness the full potential previous eras, by artificially maintaining the scarcity of their of the Internet medium. They will be able to eliminate IGs (for instance through DRM employment), and by reproduction and distribution costs, and benefit from the preserving BMs based on the sale of media goods facilitation of inter-human interaction, made possible by on- (subscription, pay-per-view). This anachronic attitude is the line operation. Furthermore, CDists will be free to employ main obstacle to CDists’ reacquisition of a useful social role. radically new technical operation schemes that optimally CDists’ remain, thus, on a techno-economic counter-current exploit Internet’s potential. Amongst such new radical path, as they resist to “letting go” of their goods’ control, solutions, to be exploited, P2P content diffusion stands most avoiding the radical new BMs and disruptive new relevantly, as it is particularly in line with the decentralizing technologies that are necessary to succeed in the on-line evolutive trend of the emerging paradigm and enables even environment on the long run. further costs reduction.

IV. THE WAY FORWARD V. THE P2P TUBE

A. A New Economic Paradigm A. Introduction The occurring establishment of a new technical paradigm The P2PTube system, is an on-line content delivery for media reproduction and distribution opens up a space of system, (under implementation), which fully harnesses the operation for the actors in that filed, which they must strive technical and economic potential of the emerging paradigm to occupy. As explained in [6], such operation implies that a in media distribution. It is defined as a hybrid P2P system for whole new economic paradigm must be embraced by the media content diffusion and user-artist interaction supported media production industry where the scarce resource to be by a donation and advertisement based BM. It maintains a harnessed is no longer the information commodity but the social interaction medium, within which, media (video) user’s attention. IGs should no longer be seen as an asset but content submission and consumption and user interaction as an investment that is made in order to achieve that goal. and rewarding take place. An Internet era BM for this activity field must thus count upon the free accessing of info goods by the user B. Business Model community, fully exploiting the potential of emerging Exploiting Internet’s potential for an automated and technologies and laterally deriving gains from the context distributed operation, P2PTube performs a distribution of the surrounding that activity [6]. For such an extraction, a costs of content reproduction, storage and distribution culture of voluntary funding and interdependency, (already throughout the user/peer community. Through the sustained on the rise), must be fostered. Artists and CDists’ operation interaction environment, users, producers and media items should be sustained by voluntary user contribution and other (MIs), interact in accordance with the following BM: indirect means (e.g. advertisement, merchandising sale, live • producer users freely supply MIs to the system, shows, etc) [6]. specifying if they expect/accept to be rewarded (by the user community) for the delivery of such items; B. A New Role for CDists • advertiser users freely supply advertising media The role previously played by CDists, is exhausted. The items to the system, specifying the level of exposure interaction space between artists and consumers has they desire for them, in terms of its cost in in-system broadened and virtualized leaving CDists in no position to credits; impose themselves as the controlling gatekeepers of the • consumer user’s freely consume any MI available in system. To maintain a useful and economically rewarding the system; role, in the Internet era, CDists must take advantage of the • all users load their accounts with real currency; opportunities offered by the emerging new technical • all users purchase in-system credits from the system: paradigm aligning their activity with its capabilities. In the o paying the system with real currency; new environment of informational abundance, they must o paying the system, with their attention, by refocus their action on capturing and maintaining user watching commercials; attention and generosity. As such, they must become the • the system sells consumer users’ attention to discoverers, promoters and managers of talented creators and advertiser users, which pay for it with in-system maximize consumer exposure to their productions. From that credits; base, they should become the weavers of consumer-artist • all users are free to donate in-system credits to affective relationships, becoming the promoters of artist- producer users they deem meritorious; consumer social interaction and bonding. It is that bonding • P2PTube taxes all donation transactions; that generates the user attention and good will that CDists • must harness, to attain economic sustainability [6]. producer users obtain revenue by extracting real currency from the system, which they obtain by C. Exploiting Technical Possibilities selling in-system credits (received as donations), Instead of resisting the ongoing technical evolution back to the system; process, CDists must take its leading edge. Once they are C. Architecture coherent interaction medium and the interfacing of the Throughout the evolution of P2P content delivery users with that medium. systems there has been a move from a hybrid centralized/P2P D. Operation operation mode (Napster), to more decentralized ones (Gnutella). This occurred for technical purposes (avoid an Each of the system’s layers develop their own internal expensive central entity), and to avoid the legal targeting of operations. Some are conducted in a centralized manner and the central provisions of such systems (e.g. the shutting others in a P2P manner, depending on the requirements of down of Napster). Still, this change has also generated those operations. problems regarding aspects such as trust, efficiency, content The IPCL, operates in a purely P2P fashion. It services discovery and others. For such reasons, in the more recent the upper layers by exchanging information packets directly past, as explained in section II, some operational between its components in different peers (Figure 2a). centralization was re-embraced, but, in a way so that a The PLL handles the validation of all exchanged compromise could be maintained between technical information packets. In every peer, the PLL signs the performance, global operation costs and legal targetability. outgoing packets (with its specific authentication data), and As P2PTube is designed to operate legally, the optimal validates the signatures of the incoming ones. The PLL also point of that compromise is necessarily different. It no longer handles the resolution of peer contact endpoints. Both such needs to avoid having a central provision. As such, it tasks are performed in a hybrid way (Figure 2b). The employs a hybrid P2P structure [2], composed by a single ultimate register and original “seeder” of the peer coordinating Core Peer (CP), and any number of, Peripheral authentication information and of the contact endpoint Peers (PP), as presented in Figure 1a. The CP, which is information is the CP’s PLL (client-server architecture). A owned and operated by P2PTube’s CDist, runs on high PP’s PLL may obtain that information from the CP’s PLL (client-server operation), or it from its fellow PPs (P2P capacity hardware, and coordinates the system. The PPs, which are owned and operated by regular users, run on operation), that have previously acquired it. Regardless of household PCs and interface the users with the system’s their origin, the data objects carrying that information are interaction environment. signed by the CP, assuring their validity.

Figure 2: Client-Server and P2P Operations for IPCLL and PLL

The UEL handles, in a client-server manner all the Figure 1: a) P2P Tube Overall Structure b) Peer Architecture operations related to the validation of user or MI identity and MI authorship rights (Figure 3a), employing the User and All peers have the same internal structure (Figure 1b). Media Item Manager (see Figure 1b). To do so, PPs’ UELs, Each peer is divided into three layers, (and so is the system, need to obtain, from the CP’s UEL, the related veracity as these layers traverse all the system’s peers): confirmation information (signature or encryption keys). The • The Inter-Peer Communication Layer (IPCL) handles original insertion or removal of content from the P2PTube is the exchanging of information packets directly between also performed, within the UEL, in a centralized fashion its components in different peers. (employing the MIMngrs). Insertion requests (and associated • The Peer Link Layer (PLL), handles the authentication MIs), and removal requests are sent from user hosting PPs, of all inter-peer communication and the resolution of to the CP, which judges their legitimacy and enforces them, peer contact endpoints. by seeding the inserted media throughout the system, or by • The Usage Environment Layer (UEL) handles the ordering all containing PPs to delete the MI, respectively. maintenance and validation of user or MI identity, the The centralized operation mode is also used in the UEL’s preservation and validation of MI authorship rights, the maintenance of user accounts and performing of currency or original indexing or removal of content, the maintenance credits transactions’. In all such cases, the CP UEL plays the of user accounts, the secure performing of currency or server role and the PP UEL, the client role. credits transactions’, the distribution of media contents, The searching and retrieval/distribution of MIs are the semantic searching for content, the maintenance of a performed, in the UEL, in a hybrid manner (Figure 3b). The core UEL instance holds all the information pertaining to the distributed storage of MIs over the system’s tissue, as well as consumption of the MI by all users and the MI semantic characterization information, against which distribution of the MI by the P2PTube user queries must be matched for content searches. It system; performs the initial seeding of the MIs and of their semantic o The MI Hash File (MIHsFile) – this file data throughout the system and then centrally coordinates the carries the SHA hash of the MI’s media P2P based search and exchange of MIs, (which is done content. directly between PPs), by informing “client” PPs about • MI Content File (MICFile) – the file carries the appropriate “server” PPs for the acquisition of desired MIs actual media (video) content of the MI; or query responses. The purpose of the MIHFile is to enable a peer to identify the MI’s owning user and thus the pubUK necessary to access the MI’s signed and ciphered contents. The MIHFile is repeated inside the MISArch and MIRCArch archives to enable peers to check the MI’s integrity. Upon deciphering those files a peer verifies if their copies of the MIHFile coincide with the one at the MI’s top. The authentication of the MIHsFile (assured by the ciphering of MIRCArch) guarantees its integrity, and its presence in the MI enables peers to verify the integrity of the MICFile. F. Security In P2PTube security and reliability are assured through Figure 3: Client-Server and P2P Operations for UEL the combination of the centralization, at the CP (at all levels), of all security sensitive aspects, and the employment E. Media Items of secure identification schemes for users, peers and MIs. At the PLL level, when joining the system, all peers specify a pair of asymmetric encryption keys, {pubPK, prvPK}. pubPK is the peer’s public key, which is registered at the CP (PLL) and prvPK is the peer’s private key, which remains in its exclusive knowledge. The same is true for the CP (PLL), whose pubPK is common knowledge amongst all PPs (PLLs). Whenever a peerA wishes to communicate with a peerB, they first agree on a common symmetric key. The Figure 4: MI Archive Structure calling peerA sends a message (pA-pB-msg), soliciting the agreement on a symmetric key (symPA-PB-K), to peerB. The P2PTube’s MIs consists of TAR archives which have the message is ciphered with peerA’s prvPK (prvPAK) and then following inner structure (depicted in Figure 4): with the destination peer’s pubPK (pubPBK). Upon • MI Head File (MIHFile) – this file carries metadata reception of pA-pB-msg, peerB deciphers it with prvPBK and indentifying the MI and its owner user; with pubPAK. In reply, peerB sends an acceptance response • MI Semantics Archive (MISArch) – this is a TAR upon which the same encryption process is repeated, but in archive which carries information for the semantic the opposite direction. From that point on, all characterization of the MI’s video content. It is communications between peerA and peerB are encrypted ciphered with the MI owner user’s prvUK (see with symPA-PB-K. The messages exchanged between peers, section V.F). It’s inner structure is the following: related to the transfer of MIs, contain, besides the message o An exact replica of the MIHFile; body, a message attachment that carries the MI. This o MI Semantics File – this file carries the attachment will not be handled in the same way as the main OWL metadata that performs the actual body, in what regards the assuring of its integrity, because semantic characterization of the MI; encrypting entire MIs would be inefficient. Instead, the • MI Rights Certification Archive (MIRCArch) – this message attachment is left unchanged, and within the is a TAR archive which carries information for the message body, the SHA hash of the attached MI, is characterization of the digital rights panorama contained. This allows the verification of the attachment’s pertaining to the MI and its usage. It is ciphered with integrity upon the message’s reception. The previously the MI owner user’s prvUK (see section V.F). It’s presented scheme enables the secure identification of the inner structure is the following: communication participants and the privacy (total or partial) o An exact replica of the MIHFile; of the transacted information. o MI License File – this file carries MPEG- At the UEL level, upon joining the system, each user 21 REL [10], metadata which describes the specifies a pair of asymmetric encryption keys, {pubUK, owner user’s reward expectations, and the prvUK} and a system wide unique watermark (Uwmk). (mandatory) permission of free pubUK is the user’s public key, which is registered at the CP (UEL) and is available for public knowledge. prvUK is the because in the emerging paradigm of information production user’s private key, which remains in his exclusive and distribution, the cornerstone of content security is no knowledge. The Uwmk is also registered at the CP, but longer content access denial, but a robust content authorship remains the knowledge of only the user and the CP. The certification. system itself also possesses it own pair of UEL level asymmetric keys {pubSK, prvSK}. G. DRM Role Whenever a user proceeds to some security sensitive As argued before, in the emerging technical and operation, (such as the manipulation of his account and its economic paradigm of information production and resources, the alteration of his declared pubUK, the initial distribution, the key aspect of digital rights protection is no connection or definitive disconnection of his peer(s) from the longer the prevention of unauthorized content access. system or the insertion or removal of MIs), the UEL level Content should be openly available and access to it, should information, that goes in the message carrying his request, be maximized. The main concern of DRM provisions must (being emitted on his behalf by the EMngr of his hosting be to, (in the less intrusive possible way), ensure that content PP’s UEL), will be ciphered with his prvUK. At the CP’s authorship is securely established and that its usurpation is UEL the user’s pubUK is employed to decipher it. This impeded. Therefore, in the P2PTube system, the DRM procedure assures that the specific user is effectively behind provisions consist of the scheme, mentioned in section V.F, the submitted request and the privacy of the communication. which involves the watermarking of MIs’ MICFiles and the At MI insertion time, the user hosting PP, watermarks construction of their internal MIRCArchs, (which implies the the media content delivered within the MI file, with the calculation of MICFiles hashes and their signature with the hosted user’s exclusive Uwmk and calculates that content’s MIs’ owning users’ prvUK). SHA hash storing it within the (appropriate component of) At content insertion time, the UEL’s DRM Manager MI. It then builds the MI’s MIRCArch, MISArch and (DRMMngr), of the user hosting PP, is employed, by the MIHFile files, encrypts the earlier two with the MI owner MIMngr, to watermark the content with the user’s exclusive user’s prvUK and assembles the entire MI (see section V.E), Uwmk and to build the respective MIRCArchs. Upon the sending it attached to the content insertion request to the CP. MI’s reception at the CP, the UEL’s DRM Manager There, the MI is extracted and validated. Its MISArch and (DRMMngr), is employed, by the MIMngr, to validate the MIRCArch files are re-encrypted with the CP’s prvSK, and signed (ciphered), contents of the MI and to verify if the the MI is rebuilt with the new version of those files. The MI delivered content contains any previous watermark from is then ready to be distributed throughout the system. The another user, other that the inserting one. The DRMMngr is veracity of an MI’s authorship declaration may be verified also employed to calculate the MI media content’s SHA1 by inspecting its respective MIRCArch. hash and to compare it to the content of the MIHsFile. If all This scheme guarantees that an MI’s authorship cannot is valid, the CP’s DRMMngr handles the re-signing of the be attributed, by anyone (including the CP), to any user, MISArch and MIRCArch files, the rebuilding of the MI and without his consent, as the prvUK, (known only to the user), the insertion process is successfully completed. In the is employed in the authentication of the MI’s contents, opposite case, the content is not accepted and the user is including in the signing (ciphering), of the media content’s sanctioned (with a mandatory payment of a certain amount hash. It also assures that other users cannot appropriate the of in-system credits), or, if his behaviour is recurrent, MI, as the watermark enables the system to detect any expelled from the user community. At content consumption insertions of illegitimate MIs. Furthermore, this scheme time, the UEL’s DRMMngr of the user hosting PP, may enables the validation of MIs’ integrity across the system as verify the integrity of the retrieved MI and the correctness of their content is signed (ciphered) or, in the case of the its authorship attribution by deciphering the MI’s MICFile, has its hash carried in the signed part of the MI. MIRCArch file, with the MI owner user’s pubUK, (obtained The resigning of the MISArch and MIRCArch files, with from the CP, or another PP), and comparing the content of the system’s prvSK, at MI insertion time enables the system the MIRCArch’s MIHsFile with the SHA hash of the MI’s peers to check if an MI has effectively been previously MICFile (that it must also calculate). processed and approved by the system. The security roles performed by the PPs, at the UEL and VI. COMPARISON PLL are possible because the CP, which is the ultimate Several real world initiatives already exist which guaranty of trust and security in the system, provides, at both successfully employ an operation and BM similar or those levels, functionalities comparable to those of a Public approximate to those we propose. Some such examples are Key Infrastructure (PKI). As such, upon PPs’ requests, the Wikipedia, The Real News Network [20], or Radiohead’s CP delivers them certificates, signed with its prvPK, and Nine Inch Nails’ experiments with voluntary user associating a user with his pubUK (at the UEL), or a peer donations. Still, none of these examples combines all of the with its pubPK (at the PLL). Given the signed nature of these necessary technical and economic parameters for an certificates, they may be securely exchanged, directly operation that fully exploits Internet’s potential. between PPs, thus, effectively, adding a P2P component to Compared with the systems and initiatives presented in the system’s PKIs. section II, P2PTube presents several technical and economic The presented MI protection scheme suffices for the advantages. Given its employment of an open access based secure P2P distribution of MIs throughout the system BM that derives gains in a lateral manner to the actual consumption of media goods, through advertisement and systems must first overcome those of an economic nature, donations, it is prepared to compete in the on-line and that is what P2PTube accomplishes. environment. As such, it has the necessary characteristics to Given its characteristics, P2PTube allows its operating attract user attention (which initiatives like ReelTime and CDist to fully harness Internet era’s economic potentials. iMesh, comparatively lack, given their subscription based The system’s employment, in a context of legality and open BMs), and to foment a culture of voluntary donations (which content access, means that the CDist and the user-creator initiatives like PPLive and Qtrax fail to do). In the technical community would have an optimally operating system. This plane, the openness of P2PTube’s BM also enables a simpler is so because it may freely centralize all tasks which demand and more efficient operation, as it does not require the it, unafraid of any legal prosecution and also because open intricate DRM provisions implied by content access and P2P media goods delivery, technically simplifies the restriction. Instead the system needs only to assure the system, greatly facilitating the elimination of reproduction integrity of the MIs which are diffused through it. In this and distribution costs. P2PTube’s established environment of manner, P2PTube provides a contextual level of security creator-consumer social bonding facilitates the development which is better than that of most systems presented in section of a voluntary support culture upon which its sustainability II, and which is simpler (and much more realistic in its and that of the creators’ activities is maintained. ambitions) than those enforced by, for instance, Qtrax, ReelTime or AXMEDIS. As a result, P2PTube is freer, than REFERENCES the three later systems, to take full advantage of content [1] Anderson, N., 2008, Five Years of Failure: EFF Says RIAA Must super-distribution. Embrace New Model, Ars Technica, http://arstechnica.com/tech- The P2PTube system does not rely on any pre-existing policy/news/2008/10/five-years-of-failure-eff-says-riaa-must- embrace-new-model.ars. 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This hybridness allows P2PTube policy/news/2007/07/p2p-traffic-shifts-away-from-music-towards- to maintain a more efficient performance in terms of content movies.ars. searching and retrieval, than most systems presented in [5] BitTorrent, 2011, Homepage, http://www.bittorrent.com/. section II (e.g. Babelgum and Joost), but simultaneously, it [6] Castro, H., Alves, A. P., Serrão, C., Caraway, B., 2010, A New does so in a more reliable way than most such systems (e.g. Paradigm for Content Producers. IEEE MultiMedia, vol. 17, no. 2, pp. 90-93, Apr. 2010. Qtrax and iMesh). It’s architecture and operation is also DOI=http://doi.ieeecomputersociety.org/10.1109/MMUL.2010.26. more uniform and less prone to coordination or global [7] iMesh, 2011, Homepage, http://www.imesh.com. management problems than AXMEDIS. [8] Joost, 2011, Homepage, http://www.joost.com/. Furthermore, given that P2PTube’s security necessities [9] Maguire, J., 2003, Hitting P2P Users Where It Hurts, WiredNews, are simpler than those of most or all systems presented in http://www.wired.com/entertainment/music/news/2003/01/57112. section II, it achieves them with greater solidity and [10] MPEG-21, 2003, MPEG-21 Information Technology — Multimedia efficiently. Framework — Part 5: Rights Expression Language, ISO/IEC JTC 1/SC 29/WG 11. VII. CONCLUSION [11] OECD, 2006, Organization for Economic Co-operation and The information production-distribution-consumption Development Information Technology Outlook 2006, http://www.oecd.org/document/1/0,3343,en_2649_34223_37486858_ field of human activity is rapidly changing. The technical, 1_1_1_1,00.html. economic and social premises which shape it are inexorably [12] PPLive, 2011, Homepage, http://www.pplive.com/en/index.html. pushing it towards an ever more collaborative production mode, and an increasingly freer exchange of information [13] Qtrax, 2011, Homepage, http://qtrax.com. goods. CDists should simply embrace this trend, by radically [14] Veoh, 2011 , Homepage, http://www.veoh.com/. changing their business and operational paradigm, striving to [15] Ratnasamy, S., Francis, P., Handley, M., Karp, R. and Shenker, S., 2001, A scalable content addressable network, Processings of the maximize their content’s exposure and social impact, and to ACM SIGCOMM. supply the consumer-creator community with captivating [16] Stoica, I., Morris, R., Karger, D., Kaashoek, M. F., and Balakrishnan, virtual social bonding spaces where content consumption and H., 2001, Chord: A scalable peer-to-peer lookup protocol for internet revenue extraction may take place. applications, Proceedings of the ACM SIGCOMM, California. The P2PTube system is inline with the ongoing evolutive [17] Zhao B., Huang L.,Stribling J.,Rhea S.,Joseph A., and Kubiatowicz trends. The breakthrough represented by this system lies in J., 2004, Tapestry: A Resilient Global-Scale Overlay for Service its economic innovativeness which then allows for it to also Deployment, IEEE Journal on Selected Areas in Communications. be technically bold and full of potential, while remaining free [18] Maymounkov, P., Maziéres, D., 2002, Kademlia: A peer-to-peer information system based on the xor metric, Proceedings of IPTPS02, of any contrived, security (or otherwise), operational USA. schemes. This is so because, in order to overcome the [19] AXMEDIS Project, 2011, Homepage, http://www.axmedis.org/. technical challenges that on-line content delivery faces, such [20] Real News, 2011, Homepage, http://www.therealnews.com.