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# System prepended metadata

title: DHTs

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# DHTs
## Contextos utilizados:
Aplicações que consegui encontrar:
* BTDigg: BitTorrent DHT search engine
    * 2011
    * Trackerless torrents: usando DHTs que detectam esses arquivos que estão sendo baixados pelos usuários, sem ter que se comunicar com o tracker centralizado. Ou seja, mesmo se os trackers caírem, você teoricamente conseguiria continuar compartilhando arquivos.
    * os torrents já tem essa tecnologia
    * o BTDigg é uma search engine pra buscar torrents nesse banco de dados da DHT
    * https://torrentfreak.com/btdigg-the-first-trackerless-torrent-search-engine-110223/
* CloudSNAP (PAAS)
    * 2011
    * Usa DHT pra fazer persistência de sessão do usuário em uma aplicação web hosteada na cloud deles (que também é tudo descentralizado, é P2P)
* Codeen
    * 2003
    * é um CDN, usa pra web caching
    * usa Sloppy DHT
    * not the value, but -- pointers to peers who have the actual value.
* Coral CDN (morto)
    * 2004-2015
    * é mesma coisa que codeen
* FAROO search engine
    * Whenever a user visits a website, it is automatically indexed and distributed to the network.
    * 2005-2013 (?)
* Freenet
    * The system, Freenet [7][8], is an Internet wide distributed hashtable (DHT) intended to strengthen the freedom of speech by allowing anyone to publish anything in the network at any time.
    * 2000
* GNUnet
    * 2001
    * is a software framework for decentralized, peer-to-peer networking and an official GNU package. The framework offers link encryption, peer discovery, resource allocation, communication over many transports (such as TCP, UDP, HTTP, HTTPS, WLAN and Bluetooth) and various basic peer-to-peer algorithms for routing, multicast and network size estimation.[6]
    * usa DHT pra file-sharing e GNS (Gnu Name System, a decentralized and censorship-resistant replacement for DNS.)
* I2P
    * 2003
    * The Invisible Internet Project (I2P) is an anonymous network layer (implemented as a Mix Network) that allows for censorship-resistant, peer to peer communication.
    * Each client application has their I2P "router" that finds other clients by querying against the fully distributed "network database" - a custom structured distributed hash table (DHT) based off the Kademlia algorithm.
* IPFS - InterPlanetary File System
    * not the value, but -- pointers to peers who have the actual value.
    * https://github.com/ipfs/go-ipfs/issues/1396
    *  is a protocol and network designed to create a content-addressable, peer-to-peer method of storing and sharing hypermedia in a distributed file system.[2] Similar to a torrent, IPFS allows users to not only receive but host content. 
* LBRY
    * a content sharing and publishing platform that is decentralized 
    * mesmo uso do ipfs, codeen, aponta pra quem tem
* Oracle Coherence
    *  distributed cache and in-memory data grid, intended for systems that require high availability, high scalability and low latency, particularly in cases that traditional relational database management systems provide insufficient throughput, or insufficient performance.
* Perfect Dark 
    * 2006
    * japanese peer-to-peer file-sharing application 
    * https://en.wikipedia.org/wiki/Perfect_Dark_(P2P)#DKT+DHT+DU
* Retroshare
    * peer-to-peer communication and file sharing app based on a friend-to-friend network
    * 2006
    * DHT p/ localizar "friends"
* Twister
    * brasileiro
    * 2013
    * peer-to-peer microblogging (estilo twitter)
    * Distribution of posts uses Kademlia distributed hash table (DHT) network 
* Storm botnet
    * botnet
    * – Peers maintain a list of other peer hashes
* Tox instant messenger
    * Tox is a peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption
    * guarda clients/friends
* YaCy search engine
    * mesma coisa que o FAROO
* Apache Cassandra
    * distributed database
    * one hop DHT.  It is more than a simple DHT because in Cassandra the values are not opaque, but they are structured into columns and columnFamilies and they are indexed.
    * http://salsahpc.indiana.edu/b534projects/sites/default/files/public/1_Cassandra%20Distributed%20Hash%20Table_Soparia%2C%20Maitrey%20Jagdish.pdf

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# DHTs
* mais relevantes (nenhuma ordem particular):
    * Mainline DHT (bittorrent)
    * CAN (content addressable network)
    * Chord
    * Tapestry
    * Pastry
    * Kademlia (mais usado?)
* BATON Overlay
* Koorde
* P-Grid
* Riak
* TomP2P
* Voldemort