Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes.
Peers make a portion of their resources, such as processing power, disk storage or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers of resources, in contrast to the traditional client-server model in which the consumption and supply of resources is divided. Emerging collaborative P2P systems are going beyond the era of peers doing similar things while sharing resources, and are looking for diverse peers that can bring in unique resources and capabilities to a virtual community thereby empowering it to engage in greater tasks beyond those that can be accomplished by individual peers, yet that are beneficial to all the peers.
While P2P systems had previously been used in many application domains, the architecture was popularized by the file sharing system Napster, originally released in 1999. The concept has inspired new structures and philosophies in many areas of human interaction. In such social contexts, peer-to-peer as a meme refers to the egalitarian social networking that has emerged throughout society, enabled by Internet technologies in general.
While P2P systems had previously been used in many application domains, the concept was popularized by file sharing systems such as the music-sharing application Napster (originally released in 1999). The peer-to-peer movement allowed millions of Internet users to connect "directly, forming groups and collaborating to become user-created search engines, virtual supercomputers, and filesystems."  The basic concept of peer-to-peer computing was envisioned in earlier software systems and networking discussions, reaching back to principles stated in the first Request for Comments, RFC 1.
Tim Berners-Lee's vision for the World Wide Web was close to a P2P network in that it assumed each user of the web would be an active editor and contributor, creating and linking content to form an interlinked "web" of links. The early Internet was more open than present day, where two machines connected to the Internet could send packets to each other without firewalls and other security measures. This contrasts to the broadcasting-like structure of the web as it has developed over the years. As a precursor to the Internet, ARPANET was a successful client-server network where "every participating node could request and serve content." However, ARPANET was not self-organized, and it lacked the ability to "provide any means for context or content-based routing beyond 'simple' address-based routing."
Therefore, USENET, a distributed messaging system that is often described as an early peer-to-peer architecture, was established. It was developed in 1979 as a system that enforces a decentralized model of control. The basic model is a client-server model from the user or client perspective that offers a self-organizing approach to newsgroup servers. However, news servers communicate with one another as peers to propagate Usenet news articles over the entire group of network servers. The same consideration applies to SMTP email in the sense that the core email-relaying network of mail transfer agents has a peer-to-peer character, while the periphery of e-mail clients and their direct connections is strictly a client-server relationship.
In May 1999, with millions more people on the Internet, Shawn Fanning introduced the music and file-sharing application called Napster. Napster was the beginning of peer-to-peer networks, as we know them today, where "participating users establish a virtual network, entirely independent from the physical network, without having to obey any administrative authorities or restrictions."
A peer-to-peer network is designed around the notion of equal peer nodes simultaneously functioning as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client–server model where communication is usually to and from a central server. A typical example of a file transfer that uses the client-server model is the File Transfer Protocol (FTP) service in which the client and server programs are distinct: the clients initiate the transfer, and the servers satisfy these requests.
Peer-to-peer networks generally implement some form of virtual overlay network on top of the physical network topology, where the nodes in the overlay form a subset of the nodes in the physical network. Data is still exchanged directly over the underlying TCP/IP network, but at the application layer peers are able to communicate with each other directly, via the logical overlay links (each of which corresponds to a path through the underlying physical network). Overlays are used for indexing and peer discovery, and make the P2P system independent from the physical network topology. Based on how the nodes are linked to each other within the overlay network, and how resources are indexed and located, we can classify networks as unstructured or structured (or as a hybrid between the two).
Unstructured peer-to-peer networks do not impose a particular structure on the overlay network by design, but rather are formed by nodes that randomly form connections to each other. (Gnutella, Gossip, and Kazaa are examples of unstructured P2P protocols).
Because there is no structure globally imposed upon them, unstructured networks are easy to build and allow for localized optimizations to different regions of the overlay. Also, because the role of all peers in the network is the same, unstructured networks are highly robust in the face of high rates of "churn"—that is, when large numbers of peers are frequently joining and leaving the network.
However, the primary limitations of unstructured networks also arise from this lack of structure. In particular, when a peer wants to find a desired piece of data in the network, the search query must be flooded through the network to find as many peers as possible that share the data. Flooding causes a very high amount of signaling traffic in the network, uses more CPU/memory (by requiring every peer to process all search queries), and does not ensure that search queries will always be resolved. Furthermore, since there is no correlation between a peer and the content managed by it, there is no guarantee that flooding will find a peer that has the desired data. Popular content is likely to be available at several peers and any peer searching for it is likely to find the same thing. But if a peer is looking for rare data shared by only a few other peers, then it is highly unlikely that search will be successful.
In structured peer-to-peer networks the overlay is organized into a specific topology, and the protocol ensures that any node can efficiently search the network for a file/resource, even if the resource is extremely rare.
The most common type of structured P2P networks implement a distributed hash table (DHT), in which a variant of consistent hashing is used to assign ownership of each file to a particular peer. This enables peers to search for resources on the network using a hash table: that is, (key, value) pairs are stored in the DHT, and any participating node can efficiently retrieve the value associated with a given key.
However, in order to route traffic efficiently through the network, nodes in a structured overlay must maintain lists of neighbors that satisfy specific criteria. This makes them less robust in networks with a high rate of churn (i.e. with large numbers of nodes frequently joining and leaving the network). More recent evaluation of P2P resource discovery solutions under real workloads have pointed out several issues in DHT-based solutions such as high cost of advertising/discovering resources and static and dynamic load imbalance.
Notable distributed networks that use DHTs include Tixati, an alternative to BitTorrent's distributed tracker, the Kad network, the Storm botnet, YaCy, and the Coral Content Distribution Network. Some prominent research projects include the Chord project, Kademlia, PAST storage utility, P-Grid, a self-organized and emerging overlay network, and CoopNet content distribution system. DHT-based networks have also been widely utilized for accomplishing efficient resource discovery for grid computing systems, as it aids in resource management and scheduling of applications.
Hybrid models are a combination of peer-to-peer and client-server models. A common hybrid model is to have a central server that helps peers find each other. Spotify was an example of a hybrid model [until 2014]. There are a variety of hybrid models, all of which make trade-offs between the centralized functionality provided by a structured server/client network and the node equality afforded by the pure peer-to-peer unstructured networks. Currently, hybrid models have better performance than either pure unstructured networks or pure structured networks because certain functions, such as searching, do require a centralized functionality but benefit from the decentralized aggregation of nodes provided by unstructured networks.
Peer-to-peer systems pose unique challenges from a computer security perspective.
Like any other form of software, P2P applications can contain vulnerabilities. What makes this particularly dangerous for P2P software, however, is that peer-to-peer applications act as servers as well as clients, meaning that they can be more vulnerable to remote exploits.
Also, since each node plays a role in routing traffic through the network, malicious users can perform a variety of "routing attacks", or denial of service attacks. Examples of common routing attacks include "incorrect lookup routing" whereby malicious nodes deliberately forward requests incorrectly or return false results, "incorrect routing updates" where malicious nodes corrupt the routing tables of neighboring nodes by sending them false information, and "incorrect routing network partition" where when new nodes are joining they bootstrap via a malicious node, which places the new node in a partition of the network that is populated by other malicious nodes.
The prevalence of malware varies between different peer-to-peer protocols. Studies analyzing the spread of malware on P2P networks found, for example, that 63% of the answered download requests on the gnutella network contained some form of malware, whereas only 3% of the content on OpenFT contained malware. In both cases, the top three most common types of malware accounted for the large majority of cases (99% in gnutella, and 65% in OpenFT). Another study analyzing traffic on the Kazaa network found that 15% of the 500,000 file sample taken were infected by one or more of the 365 different computer viruses that were tested for.
Corrupted data can also be distributed on P2P networks by modifying files that are already being shared on the network. For example, on the FastTrack network, the RIAA managed to introduce faked chunks into downloads and downloaded files (mostly MP3 files). Files infected with the RIAA virus were unusable afterwards and contained malicious code. The RIAA is also known to have uploaded fake music and movies to P2P networks in order to deter illegal file sharing. Consequently, the P2P networks of today have seen an enormous increase of their security and file verification mechanisms. Modern hashing, chunk verification and different encryption methods have made most networks resistant to almost any type of attack, even when major parts of the respective network have been replaced by faked or nonfunctional hosts.
The decentralized nature of P2P networks increases robustness because it removes the single point of failure that can be inherent in a client-server based system. As nodes arrive and demand on the system increases, the total capacity of the system also increases, and the likelihood of failure decreases. If one peer on the network fails to function properly, the whole network is not compromised or damaged. In contrast, in a typical client–server architecture, clients share only their demands with the system, but not their resources. In this case, as more clients join the system, fewer resources are available to serve each client, and if the central server fails, the entire network is taken down.
There are both advantages and disadvantages in P2P networks related to the topic of data backup, recovery, and availability. In a centralized network, the system administrators are the only forces controlling the availability of files being shared. If the administrators decide to no longer distribute a file, they simply have to remove it from their servers, and it will no longer be available to users. Along with leaving the users powerless in deciding what is distributed throughout the community, this makes the entire system vulnerable to threats and requests from the government and other large forces. For example, YouTube has been pressured by the RIAA, MPAA, and entertainment industry to filter out copyrighted content. Although server-client networks are able to monitor and manage content availability, they can have more stability in the availability of the content they choose to host. A client should not have trouble accessing obscure content that is being shared on a stable centralized network. P2P networks, however, are more unreliable in sharing unpopular files because sharing files in a P2P network requires that at least one node in the network has the requested data, and that node must be able to connect to the node requesting the data. This requirement is occasionally hard to meet because users may delete or stop sharing data at any point.
In this sense, the community of users in a P2P network is completely responsible for deciding what content is available. Unpopular files will eventually disappear and become unavailable as more people stop sharing them. Popular files, however, will be highly and easily distributed. Popular files on a P2P network actually have more stability and availability than files on central networks. In a centralized network, a simple loss of connection between the server and clients is enough to cause a failure, but in P2P networks, the connections between every node must be lost in order to cause a data sharing failure. In a centralized system, the administrators are responsible for all data recovery and backups, while in P2P systems, each node requires its own backup system. Because of the lack of central authority in P2P networks, forces such as the recording industry, RIAA, MPAA, and the government are unable to delete or stop the sharing of content on P2P systems.
In P2P networks, clients both provide and use resources. This means that unlike client-server systems, the content-serving capacity of peer-to-peer networks can actually increase as more users begin to access the content (especially with protocols such as Bittorrent that require users to share, refer a performance measurement study). This property is one of the major advantages of using P2P networks because it makes the setup and running costs very small for the original content distributor.
Peer-to-peer networking involves data transfer from one user to another without using an intermediate server. Companies developing P2P applications have been involved in numerous legal cases, primarily in the United States, over conflicts with copyright law. Two major cases are Grokster vs RIAA and MGM Studios, Inc. v. Grokster, Ltd.. In the last case, the Court unanimously held that defendant peer-to-peer file sharing companies Grokster and Streamcast could be sued for inducing copyright infringement.
Cooperation among a community of participants is key to the continued success of P2P systems aimed at casual human users; these reach their full potential only when large numbers of nodes contribute resources. But in current practice, P2P networks often contain large numbers of users who utilize resources shared by other nodes, but who do not share anything themselves (often referred to as the "freeloader problem"). Freeloading can have a profound impact on the network and in some cases can cause the community to collapse. In these types of networks "users have natural disincentives to cooperate because cooperation consumes their own resources and may degrade their own performance."  Studying the social attributes of P2P networks is challenging due to large populations of turnover, asymmetry of interest and zero-cost identity. A variety of incentive mechanisms have been implemented to encourage or even force nodes to contribute resources.
Some researchers have explored the benefits of enabling virtual communities to self-organize and introduce incentives for resource sharing and cooperation, arguing that the social aspect missing from today's P2P systems should be seen both as a goal and a means for self-organized virtual communities to be built and fostered. Ongoing research efforts for designing effective incentive mechanisms in P2P systems, based on principles from game theory, are beginning to take on a more psychological and information-processing direction.
Some peer-to-peer networks (e.g. Freenet) place a heavy emphasis on privacy and anonymity—that is, ensuring that the contents of communications are hidden from eavesdroppers, and that the identities/locations of the participants are concealed. Public key cryptography can be used to provide encryption, data validation, authorization, and authentication for data/messages. Onion routing and other mix network protocols (e.g. Tarzan) can be used to provide anonymity.
Although peer-to-peer networks can be used for legitimate purposes, rights holders have targeted peer-to-peer over the involvement with sharing copyrighted material. Peer-to-peer networking involves data transfer from one user to another without using an intermediate server. Companies developing P2P applications have been involved in numerous legal cases, primarily in the United States, primarily over issues surrounding copyright law. Two major cases are Grokster vs RIAA and MGM Studios, Inc. v. Grokster, Ltd. In both of the cases the file sharing technology was ruled to be legal as long as the developers had no ability to prevent the sharing of the copyrighted material. To establish criminal liability for the copyright infringement on peer-to-peer systems, the government must prove that the defendant infringed a copyright willingly for the purpose of personal financial gain or commercial advantage. Fair use exceptions allow limited use of copyrighted material to be downloaded without acquiring permission from the rights holders. These documents are usually news reporting or under the lines of research and scholarly work. Controversies have developed over the concern of illegitimate use of peer-to-peer networks regarding public safety and national security. When a file is downloaded through a peer-to-peer network, it is impossible to know who created the file or what users are connected to the network at a given time. Trustworthiness of sources is a potential security threat that can be seen with peer-to-peer systems.
A study ordered by the European Union found that illegal downloading may lead to an increase in overall video game sales because newer games charge for extra features or levels. The paper concluded that piracy had a negative financial impact on movies, music, and literature. The study relied on self-reported data about game purchases and use of illegal download sites. Pains were taken to remove effects of false and misremembered responses.
Peer-to-peer applications present one of the core issues in the network neutrality controversy. Internet service providers (ISPs) have been known to throttle P2P file-sharing traffic due to its high-bandwidth usage. Compared to Web browsing, e-mail or many other uses of the internet, where data is only transferred in short intervals and relative small quantities, P2P file-sharing often consists of relatively heavy bandwidth usage due to ongoing file transfers and swarm/network coordination packets. In October 2007, Comcast, one of the largest broadband Internet providers in the United States, started blocking P2P applications such as BitTorrent. Their rationale was that P2P is mostly used to share illegal content, and their infrastructure is not designed for continuous, high-bandwidth traffic. Critics point out that P2P networking has legitimate legal uses, and that this is another way that large providers are trying to control use and content on the Internet, and direct people towards a client-server-based application architecture. The client-server model provides financial barriers-to-entry to small publishers and individuals, and can be less efficient for sharing large files. As a reaction to this bandwidth throttling, several P2P applications started implementing protocol obfuscation, such as the BitTorrent protocol encryption. Techniques for achieving "protocol obfuscation" involves removing otherwise easily identifiable properties of protocols, such as deterministic byte sequences and packet sizes, by making the data look as if it were random. The ISP's solution to the high bandwidth is P2P caching, where an ISP stores the part of files most accessed by P2P clients in order to save access to the Internet.
Researchers have used computer simulations to aid in understanding and evaluating the complex behaviors of individuals within the network. "Networking research often relies on simulation in order to test and evaluate new ideas. An important requirement of this process is that results must be reproducible so that other researchers can replicate, validate, and extend existing work."  If the research cannot be reproduced, then the opportunity for further research is hindered. "Even though new simulators continue to be released, the research community tends towards only a handful of open-source simulators. The demand for features in simulators, as shown by our criteria and survey, is high. Therefore, the community should work together to get these features in open-source software. This would reduce the need for custom simulators, and hence increase repeatability and reputability of experiments." 
Besides all the above stated facts, there have been work done on ns-2 open source network simulator. One research issue related to free rider detection and punishment has been explored using ns-2 simulator here.
An anonymous P2P communication system is a peer-to-peer distributed application in which the nodes, which are used to share resources, or participants are anonymous or pseudonymous. Anonymity of participants is usually achieved by special routing overlay networks that hide the physical location of each node from other participants.
Interest in anonymous P2P systems has increased in recent years for many reasons, ranging from the desire to share files without revealing one's network identity and risking litigation to distrust in governments, concerns over mass surveillance and data retention, and lawsuits against bloggers.BitChute
BitChute is a video hosting service that uses peer-to-peer WebTorrent technology in order to diffuse, redistribute, and ease bandwidth and issues of centralized streaming.Content delivery network
A content delivery network or content distribution network (CDN) is a geographically distributed network of proxy servers and their data centers. The goal is to provide high availability and high performance by distributing the service spatially relative to end-users. CDNs serve a large portion of the Internet content today, including web objects (text, graphics and scripts), downloadable objects (media files, software, documents), applications (e-commerce, portals), live streaming media, on-demand streaming media, and social media sites.CDNs are a layer in the internet ecosystem. Content owners such as media companies and e-commerce vendors pay CDN operators to deliver their content to their end users. In turn, a CDN pays ISPs, carriers, and network operators for hosting its servers in their data centers.
CDN is an umbrella term spanning different types of content delivery services: video streaming, software downloads, web and mobile content acceleration, licensed/managed CDN, transparent caching, and services to measure CDN performance, load balancing, multi-CDN switching and analytics and cloud intelligence. CDN vendors may cross over into other industries like security, with DDoS protection and web application firewalls (WAF), and WAN optimization.File sharing
File sharing is the practice of distributing or providing access to digital media, such as computer programs, multimedia (audio, images and video), documents or electronic books. File sharing may be achieved in a number of ways. Common methods of storage, transmission and dispersion include manual sharing utilizing removable media, centralized servers on computer networks, World Wide Web-based hyperlinked documents, and the use of distributed peer-to-peer networking.Napster
Napster is a set of three music-focused online services. It was founded as a pioneering peer-to-peer (P2P) file sharing Internet service that emphasized sharing digital audio files, typically audio songs, encoded in MP3 format. The company ran into legal difficulties over copyright infringement. It ceased operations and was eventually acquired by Roxio. In its second incarnation, Napster became an online music store until it was acquired by Rhapsody from Best Buy on December 1, 2011.
Later, more decentralized projects followed Napster's P2P file-sharing example, such as Gnutella, Freenet, BearShare and Soulseek. Some services, like LimeWire, Scour, Kazaa, Grokster, Madster, and eDonkey2000, were also brought down or changed due to copyright issues.P2P Foundation
P2P Foundation: The Foundation for Peer to Peer Alternatives is an organization with the aim of studying the impact of peer to peer technology and thought on society. It was founded by Michel Bauwens, James Burke and Brice Le Blévennec.The P2P Foundation is a registered institute founded in Amsterdam, Netherlands. Its local registered name is: Stichting Peer to Peer Alternatives, dossier nr: 34264847.Peer-to-peer banking
Peer-to-peer banking is a term used in the blockchain banking industry and designates an act of transfer of value without the need of an intermediary such as a bank.
Peer-to-peer banking is an online system that allows individual members to complete financial transactions with one another by using an auction style process that lets members offer loans for a specific amount and at a specific rate.Peer-to-peer carsharing
Peer-to-peer carsharing (also known as person-to-person carsharing and peer-to-peer car rental) is the process whereby existing car owners make their vehicles available for others to rent for short periods of time.
Peer-to-peer carsharing is a form of person-to-person lending or collaborative consumption, as part of the sharing economy. The business model is closely aligned with traditional car clubs such as Streetcar or Zipcar, but replaces a typical fleet with a ‘virtual’ fleet made up of vehicles from participating owners. With peer-to-peer carsharing, participating car owners are able to charge a fee to rent out their vehicles when they are not using them. Participating renters can access nearby and affordable vehicles and pay only for the time they need to use them.
Businesses within this sector screen participants (both owners and renters) and offer a technical platform, usually in the form of a website and mobile app, that brings these parties together, manages rental bookings and collects payment. Businesses take between 25% and 40% of the total income, which covers borrower/renter insurance, operating expenses, and roadside assistance.
As with person-to-person lending, the Internet and the adoption of location-based services have contributed to the growth of peer-to-peer carsharing.Peer-to-peer file sharing
Peer-to-peer file sharing is the distribution and sharing of digital media using peer-to-peer (P2P) networking technology. P2P file sharing allows users to access media files such as books, music, movies, and games using a P2P software program that searches for other connected computers on a P2P network to locate the desired content. The nodes (peers) of such networks are end-user computers and distribution servers (not required).
Peer-to-peer file sharing technology has evolved through several design stages from the early networks like Napster, which popularized the technology, to the later models like the BitTorrent protocol. Microsoft uses it for Update distribution (Windows 10) and online playing games (e.g. the mmorpg Skyforge) use it as their content distribution network for downloading large amounts of data without incurring the dramatic costs for bandwidth inherent when providing just a single source.
Several factors contributed to the widespread adoption and facilitation of peer-to-peer file sharing. These included increasing Internet bandwidth, the widespread digitization of physical media, and the increasing capabilities of residential personal computers. Users are able to transfer one or more files from one computer to another across the Internet through various file transfer systems and other file-sharing networks.Peer-to-peer lending
Peer-to-peer lending, also abbreviated as P2P lending, is the practice of lending money to individuals or businesses through online services that match lenders with borrowers. Since peer-to-peer lending companies offering these services generally operate online, they can run with lower overhead and provide the service more cheaply than traditional financial institutions. As a result, lenders can earn higher returns compared to savings and investment products offered by banks, while borrowers can borrow money at lower interest rates, even after the P2P lending company has taken a fee for providing the match-making platform and credit checking the borrower. There is the risk of the borrower defaulting on the loans taken out from peer-lending websites.
Also known as crowdlending, many peer-to-peer loans are unsecured personal loans, though some of the largest amounts are lent to businesses. Secured loans are sometimes offered by using luxury assets such as jewelry, watches, vintage cars, fine art, buildings, aircraft and other business assets as collateral. They are made to an individual, company or charity. Other forms of peer-to-peer lending include student loans, commercial and real estate loans, payday loans, as well as secured business loans, leasing, and factoring.The interest rates can be set by lenders who compete for the lowest rate on the reverse auction model or fixed by the intermediary company on the basis of an analysis of the borrower's credit. The lender's investment in the loan is not normally protected by any government guarantee. On some services, lenders mitigate the risk of bad debt by choosing which borrowers to lend to, and mitigate total risk by diversifying their investments among different borrowers. Other models involve the P2P lending company maintaining a separate, ringfenced fund, such as RateSetter's Provision Fund, which pays lenders back in the event the borrower defaults, but the value of such provision funds for lenders is subject to debate.The lending intermediaries are for-profit businesses; they generate revenue by collecting a one-time fee on funded loans from borrowers and by assessing a loan servicing fee to investors (tax-disadvantaged in the UK vs charging borrowers) or borrowers (either a fixed amount annually or a percentage of the loan amount). Compared to stock markets, peer-to-peer lending tends to have both less volatility and less liquidity.Peer-to-peer ridesharing
Peer-to-peer ridesharing can be divided along the spectrum from commercial, for-fee transportation network companies (TNC) to for-profit ridesharing services to informal nonprofit peer-to-peer carpooling arrangements. The term transportation network company comes from a 2013 California Public Utilities Commission ruling that decided to make the TNC revenue model legal.Essentially all modern peer-to-peer ridesharing schemes rely on web application and mobile app technology.Peer-to-peer web hosting
Peer-to-peer web hosting is using peer-to-peer networking to distribute access to webpages. This is differentiated from the client–server model which involves the distribution of Web data between dedicated web servers and user-end client computers.
P2P web hosting may take the form of P2P web caches ( and content delivery networks like Dijjer and Coral Cache which allow users to hold copies of data from single web pages and distribute the caches with other users for faster access during peak traffic.Peercasting
Peercasting is a method of multicasting streams, usually audio and/or video, to the Internet via peer-to-peer technology. It can be used for commercial, independent, and amateur multicasts. Unlike traditional IP Multicast, peercasting can facilitate on-demand content delivery.Peercoin
Peercoin, also known as PPCoin or PPC, is a peer-to-peer cryptocurrency utilizing both proof-of-stake and proof-of-work systems.
Peercoin is based on an August 2012 paper which listed the authors as Scott Nadal and Sunny King. King, who also created Primecoin, is a pseudonym. The Peercoin source code is distributed under the MIT/X11 software license.
In the proof-of-stake system, new coins are generated based on the holdings of individuals. In other words, someone holding 1% of the currency will generate 1% of all proof-of-stake coin blocks. This has the effect of making a monopoly more costly, and separates the risk of a monopoly from proof-of-work mining shares.Private peer-to-peer
Private peer-to-peer (P2P) systems are peer-to-peer (P2P) systems that allow only mutually trusted peers to participate. This can be achieved by using a central server such as a Direct Connect hub to authenticate clients. Alternatively, users can exchange passwords or cryptographic keys with friends to form a decentralized network. Private peer-to-peer systems can be divided into friend-to-friend (F2F) and group-based systems. Friend-to-friend systems only allow connections between users who know one another, but may also provide automatic anonymous forwarding. Group-based systems allow any user to connect to any other, and thus they cannot grow in size without compromising their users' privacy. Some software, such as WASTE, can be configured to create either group-based or F2F networks.Sharing economy
The sharing economy, also known as the access economy, peer-to-peer (P2P) economy, or collaborative economy is a mode of consumption whereby goods and services are not owned by a single user, but rather only temporarily accessed by members of a network and underutilized assets are shared, either for free or for a fee. It includes "sharing, bartering, lending, trading, renting, gifting, and swapping redefined through technology and peer communities." Other examples include: exchanging, collective purchasing, shared ownership, shared value, borrowing, and subscription based models. It is based on the idea that having access to a good or a service can be preferable to having ownership of such good or service and that there are benefits to collaboration in ownership. It refers to a hybrid market model of peer-to-peer exchange.The access economy has grown with information technology and is now primarily facilitated by intermediaries or brokers via websites and mobile apps. Uberisation refers to the rise of the access economy.In 2015, $26 billion in transactions were a result of the access economy.The access economy faces regulatory and political challenges, such as: defining the nature of the employment relationship between the facilitator and the service provider; designing regulations to safeguard parties to access economy transactions; taxation; and compliance with legacy regulations, such as the long-time requirement for taxi drivers to provide wheelchair vans.The sharing economy can refer to social peer-to-peer processes that include sharing of access to goods and services, or any rental transaction facilitated by a two-sided market, including business to consumer (B2C). For this reason, the term sharing economy has been criticised as misleading, as some argue that even services that enable peer-to-peer exchange can be primarily profit-driven.The sharing economy is related to the circular economy, which minimizes waste and includes co-operatives, co-creation, recycling, upcycling, re-distribution, and trading used goods. It is also closely related to collaborative consumption in which an item is consumed by multiple people.Social peer-to-peer processes
Social peer-to-peer processes are interactions with a peer-to-peer dynamic. These peers can be humans or computers. Peer-to-peer (P2P) is a term that originated from the popular concept of the P2P distributed computer application architecture which partitions tasks or workloads between peers. This application structure was popularized by file sharing systems like Napster, the first of its kind in the late 1990s.
The concept has inspired new structures and philosophies in many areas of human interaction. P2P human dynamic affords a critical look at current authoritarian and centralized social structures. Peer-to-peer is also a political and social program for those who believe that in many cases, peer-to-peer modes are a preferable option.WebRTC
Yourdrive is a New Zealand peer-to-peer carsharing company. It facilitates a system in which individuals may rent their privately owned vehicles on an hourly, daily or weekly basis to other registered users of the service. Owners set their rental prices and earn a 60 percent commission from the rental revenue. It currently operates in throughout New Zealand with vehicles in Auckland, Hamilton, Palmerston North, Wellington, Christchurch, Dunedin.
New Zealand rental car firm JUCY purchased 50% of the company in 2016Peer-to-peer carsharing is an example of collaborative consumption, where assets and skills are shared or traded between neighbours for sustainability and economic benefit. Although car sharing is relatively new in New Zealand it is an area that is being encouraged due to the environmental and economic benefits. Auckland Transport is promoting a scheme that would drastically increase the number of car sharing vehicles.
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