Internet Engineering Task Force J. Pouwelse, Ed. Internet-Draft Delft University of Technology Intended status: Standards Track October 22, 2012 Expires: April 25, 2013 Media without censorship (CensorFree) scenarios draft-pouwelse-censorfree-scenarios-02 Abstract This document describes some scenarios in which one can imagine that the ability of authoritarian regime to censor news dissemination is reduced. It tries to draw some conclusions about what's desirable and what's not acceptable for users in those scenarios. The CensorFree objective is to standardize the protocols for microblogging on smartphones with a focus on security and censorship resistance. Microblog entries are short text messages, possibly enriched with pictures or streaming video. The goal is to devise protocols which guard against all known forms of censorship such as: cyberspace sabotage, digital eavesdropping, infiltration, fraud, Internet kill switches and lawyer-based attacks with the best known protective methods. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 25, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Pouwelse Expires April 25, 2013 [Page 1] Internet-Draft CensorFree October 2012 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Goal: microblogging . . . . . . . . . . . . . . . . . . . . . 4 4. Driving scenarios . . . . . . . . . . . . . . . . . . . . . . 5 4.1. 20sec scenario . . . . . . . . . . . . . . . . . . . . . . 6 4.1.1. Adversary model: A simplistic attacker . . . . . . . . 6 4.1.2. Scenario details and architectural requirements . . . 6 4.2. Kill-switch scenario . . . . . . . . . . . . . . . . . . . 8 4.2.1. Adversary model: An advanced attacker . . . . . . . . 8 4.2.2. Scenario details and architectural requirements . . . 8 4.3. friend-to-friend scenario . . . . . . . . . . . . . . . . 9 4.3.1. Adversary model: A powerful attacker . . . . . . . . . 9 4.3.2. Scenario details and architectural requirements . . . 10 4.4. Transmorph ability . . . . . . . . . . . . . . . . . . . . 10 4.5. A single global conversation . . . . . . . . . . . . . . . 11 4.6. Spammers and hoaxes . . . . . . . . . . . . . . . . . . . 11 5. Design principles: simplicity and prior success . . . . . . . 12 6. Background rant: lack of coordination and fragmentation . . . 12 7. Current running code and related work . . . . . . . . . . . . 13 8. Open issues . . . . . . . . . . . . . . . . . . . . . . . . . 14 8.1. Use cases and threat model . . . . . . . . . . . . . . . . 15 8.2. System components, definitions and system architecture . . 15 8.3. Current technology and gap . . . . . . . . . . . . . . . . 15 8.4. Detailed system design and protocol specification . . . . 15 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 11.1. Normative References . . . . . . . . . . . . . . . . . . . 15 11.2. Informative References . . . . . . . . . . . . . . . . . . 15 11.3. URL References . . . . . . . . . . . . . . . . . . . . . . 15 Pouwelse Expires April 25, 2013 [Page 2] Internet-Draft CensorFree October 2012 1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 2. Introduction Bits moving across the Internet are vulnerable to surveillance and censorship on an unprecedented scale. Today, both Internet providers and governments possess the ability to monitor the moves of their digital citizens from central infrastructure points. This monitor ability creates significant potential for abuse, and a threat that goes beyond the scope of mere monitoring or filtering. Governments have demonstrated their ability to disable communications networks in times of crisis. During the 2011 Arab Spring, Egyptian authorities demanded that telecommunication companies sever their broadband connections and mobile networks--both local and European operators were forced to comply, and, as a result, digital Egypt vanished. Despite the country's decentralized infrastructure, an Internet blackout was relatively easy to carry out. The roles and consequences of social media (e.g., Facebook and Twitter) during that same period further illustrate the capacity governments have for Internet censorship and the challenges activists face in combating it. The April 6 Youth Movement from Egypt committed digital dissent in full public view. According to The New York Times[YOUTH], the movement "provided a structure for a new generation of Egyptians, who aren't part of the nation's small coterie of activists and opinion makers, to assemble virtually and communicate freely about their grievances." But moving protest organizations to social media accessible to the public-at-large can hold surprising risks. On the ground, the movement's organization of labor strikes and protests in Facebook groups, many with thousands of followers, triggered arrest and imprisonment. Protesters in other countries quickly took note of Egypt's lesson and disabled their public Facebook profiles. In response, one government initiated social media searches on incoming, young, plane travelers by forcing them to login to Facebook upon arrival, thereby revealing online activities and any anti-government sympathies.[FORCEDLOGIN] A glimmer of hope exists. The Arab Spring shows that a new generation is claiming their right to express themselves. Microblogging, social media in general and traditional satellite news broadcast networks are perceived as critical catalysts for political change. Generic computational fabric is soon getting in the hands of two billion people with the growth of smartphones and increasingly affordable communication. These smartphones are increasingly used to Pouwelse Expires April 25, 2013 [Page 3] Internet-Draft CensorFree October 2012 record and spread disruptive audiovisual material, even in regions without media freedom. Democratic countries also face a dilemma. Restrictions on the free information flow is the topics of several proposed laws by elected representatives. The strength of copyright law impacts digital information flow. Politicians must decide between weak copyright law, as championed by civil rights activists versus strong copyright enforcement, as promoted by numerous players in the creative industries. Recent furor around SOPA, PIPA, etc. in the US plus the European Parliament vote on ACTA is highly relevant in this context. The uniqueness of The Internet lies in the IETF standards. Moving certain bits to certain locations or offering a service requires no prior official approval. However, Internet-deployed mechanisms now exist which filter news and media in general for both surveillance and censorship. The Internet has ceased to provide reliable transport service for all users. The IETF can repeat it's historical inter-networking role again by setting the standard for reliable flow of packets of news. 3. Goal: microblogging The goal is creating a microblogging standard and facilitating a reference implementation for portable devices which is capable of operating in a hostile environment. This standard should be resilient against a government Internet kill switch. Microblogging is an increasingly popular technology for lightweight interaction over the Internet. It differs from traditional blogging in that [OPENMICRO]: o Posts are short (typically less than 140 characters, which is the limit in SMS). o Posts are in plain text. o People can reply to your posts, but not directly comment on them. o People learn about your posts only if they have permission to view them. o Your microblogging feed is discovered based on your identity at a domain or with a service. This proposed draft standard SHALL provide: "information dissemination from a single smartphone to an audience of millions in the form of microblogging, enriched with pictures or streaming video which is guarded against all known forms of censorship such as: Pouwelse Expires April 25, 2013 [Page 4] Internet-Draft CensorFree October 2012 cyberspace sabotage, digital eavesdropping, infiltration, fraud, Internet kill switches and lawyer-based attacks with the best known protective methods". The focus on microblogging is driven by feasibility. Creating a standard for overcoming censorship for social networks, search engines or web browsing in general is extremely challenging. Mitigating the threats posed by Internet kill switches requires focus on the most feasible viable standard. The related work listed in this document shows existing operational systems. Existing systems cover all functionality we desire, however none of them cover all aspects and little interoperability exists. As early as 2006, long before Arab spring events, it was reported that individuals in wide swathes of the Arab world were using Bluetooth technology to bypass police restrictions. According to news reports[DATING], communication between men and women in this region had been made possible by cellphone technology. When Bluetooth-capable phones are in close proximity, they can engage directly in digital and social chatter--no other infrastructure is needed. Moreover, when sharing photos or bandwidth-hungry videos with friends it also pays to be close. Government provided cellphone networks might not be filtering you, but can still be dreadfully slow. It therefore pays to use cell phones' Bluetooth-based, direct file-transfer features--and it comes as no surprise that wireless- transfer apps have seen millions of installs. A query of Google Trends for the phrase "Bluetooth transfer" reveals a geographical spread of this interesting social phenomenon[TREND]. It seems millions of mobile phone owners are already employing the social practice of wireless data exchange. Viability is increased by building upon this practice. 4. Driving scenarios Recent Arab spring events have shown the power of ubiquitous camera- phones, new media and microblogging. This document proposes to uses smartphones, wifi and USB sticks for multimedia transport and playback. The architecture, features and driving scenarios are specifically crafted to enable compliant implementations as a single smartphone app without any additional server infrastructure. Each scenario is focused on certain threats in a hostile environment. The adversary becomes stronger in several of the following scenarios and we also focus on the social media context. Pouwelse Expires April 25, 2013 [Page 5] Internet-Draft CensorFree October 2012 4.1. 20sec scenario First scenario, called "20sec", defines an open microblogging standard. This first scenario duplicates existing microblogging practices with an open standard in a fully decentralized setting. The scenario requirements are performance equal to central-server based approach (e.g. the ability to reach 20 million people in 20 seconds). 4.1.1. Adversary model: A simplistic attacker Eavesdropping is a common and easy passive attack in a hostile environment. In this scenario we assume the attacker has full access to the network between the user and any Internet server. Specifically, the adversary can observe, block, delay, replay and modify all traffic coming from any server. Furthermore, all servers such as DNS servers, web servers, swarm trackers, CDN cloud servers and access portals are assumed to be under direct or indirect control of the adversary. The adversary cannot compromise traffic between smartphones or other participating devices. The adversary cannot compromise smartphones or other participating devices. The adversary cannot break standard cryptographic primitives, such as block ciphers and message- authentication codes. 4.1.2. Scenario details and architectural requirements Smartphone owner Alice with wifi-based Internet access records an eye witness video. She attaches this video to a microblog entry and shares this story plus video automatically with friends Bob and Charlie which are subscribed to her news feed. Alice does not need to trust any central server with her credentials or has to prove her identity to a central (web) server. Bob and Charlie are both behind a NAT middlebox compliant to the BEHAVE recommendations [RFC4787]. No assistance of a coordinating server (e.g. STUN or TURN) is required to traverse this NAT box using UDP messages. This scenario assumes direct or NAT-based Internet access (the next scenario deals with packet forwarding). Performance should be equal to central-server based approach, providing the ability to reach 20 million people in 20 seconds. This first scenario duplicates existing microblogging practices with an open standard in a fully decentralized setting. The 20sec scenario requires that solutions provide seamless backwards compatibility with existing leading solutions (e.g. Twitter, Sina Weibo, chyrp, heello) by using content import tools. Proposed open solutions MUST permit easy bulk trans-coding and ingest of existing news feeds into this Pouwelse Expires April 25, 2013 [Page 6] Internet-Draft CensorFree October 2012 open standard. An essential feature of the 20sec scenario is all central gatekeepers or communication to them is possibly compromised. Ownership of data is fundamental to autonomy. To meet the anti-censorship goal, 20sec assumes an infrastructure which is not dependent and completely decoupled from potentially hostile servers such as DNS servers and web servers. 20sec MUST be based on full self-organization. The infrastructure consists purely of devices running compliant implementations. No central server requires installation or maintenance, making this infrastructure independent on any type of funding or business model. 20sec requires an overlay which is highly resilient. Smartphones, tablets and PCs are able to utilize this P2P overlay for microblogging. Existing solutions such as [OPENMICRO] require a central webserver and OAuth-like authentication primitives. This prior work is not suitable for our 20sec scenario, as we aim to remove all server, ultrapeer or superpeer reliance and equality of all participants in the overlay. When Alice downloads her smartphone app and starts it for the first time it needs to bootstrap. On this initial startup, the microblogging software must bootstrap and find at least one other peer in the overlay. The most simple method of bootstrapping is using a list of currently online peers plus their port number. See the example below. # file: Central-Bootstrap-Servers.txt # default bootstrap peers server1.always-online.org 6420 host1.never-offline.ro 6420 sealand.routed.org 6420 168.0.0.13 6420 A file sharing program needs a fresh list of peers to bootstrap. Thus a pre-defined list of peers is included in the software installer. As peers can go offline it is important that at least one peer out of possibly thousands on the list is still online. This pre-existing address list of possibly working peers must therefore remain valid for as long as possible. Bootstrapping is done by contacting peers in the list, possibly in parallel. If a single peers replies, the smartphone app of Alice is connected. Once connected, a fresh list of working peer Internet addresses COULD be requested. Several ideas have been proposed on bootstrapping systems without an "online bootstrap server" list. For instance, simply by smart brute force pinging, as described by the University of Denver [BOOTSTRAP]. It is RECOMMENDED compliant implementations explore and implement Pouwelse Expires April 25, 2013 [Page 7] Internet-Draft CensorFree October 2012 efficient alternatives for decentralized initial bootstrapping. 4.2. Kill-switch scenario This scenario describes a situation without any Internet access. We assume the government has essentially "killed" the Internet, in an Arab spring like scenario. It is focused on ad-hoc packet forwarding between smartphones. 4.2.1. Adversary model: An advanced attacker The adversary has disabled all Internet-based communication. We assume the adversary cannot eavesdrop, jam, delay, replay, modify or spoof wireless communication between smartphones. The adversary cannot compromise smartphones or other participating devices. The adversary cannot break standard cryptographic primitives, such as block ciphers and message-authentication codes. 4.2.2. Scenario details and architectural requirements Smartphone owner Alice has no Internet access. She records a video, attaches this video to a microblog entry in her phone app. Friends Bob and Charlie are subscribed to her news feed. Bob and Charlie are at some point within range of the wifi, bluetooth or other wireless capability of Alice. This fresh microblog entry plus video is shared automatically. Bob obtained the message from Alice using a smartphone app which is periodically scanning if other devices are around and if they possibly have fresh news. This periodic synchronization SHOULD be energy-efficient. Bob sees no noticeable decrease in battery lifetime after he obtained unconstrained news access. Charlie later goes to a square where numerous people have gathered, most of which are highly interested in the latest videos. The fresh messages automatically spreads in this crowd. Note that this scenario differs from Delay-Tolerant Networking (DTN), as being investigated by a Working Group within the Internet Research Task Force [RFC4838] and scientists[BUBBLE]. The DTN focus is on finding routes to an explicitly given destination, usually by maintaining routing tables. Their system model and terminology cannot be applied in our context, for instance, "Endpoint Identifiers" which identify the original sender and final destination. In our Internet-Free scenario sender Alice does NOT explicitly send a message with destination Bob. A wealth of related work exists in this area. General solutions are found in mobile ad hoc networks (MANET), which provide self-organized IP routing among wireless devices, and delay-tolerant networks (DTN), Pouwelse Expires April 25, 2013 [Page 8] Internet-Draft CensorFree October 2012 which use a simple store-and-forward primitive to communicate over heterogeneous links. Mobile ad hoc networks have been studied within the Internet Research Task Force (IRTF) since 1997, leading to several standards published by the IETF's MANET Working Group, while delay-tolerant networks are currently the focus of the IRTF's DTN Research Group. We hope that much of that knowledge can be reused, despite our scenario differing slightly from DTN (as being investigated by the IRTF [RFC4838]) 4.3. friend-to-friend scenario This third scenario uses friend-to-friend networking to remove the requirement for active networking and wifi sensing. The smartphones of Alice and Bob need to be synced manually. This scenario SHOULD deliver a privacy-by-design type of microblogging service. 4.3.1. Adversary model: A powerful attacker We must assume from the Arab Spring scenario the existence of a powerful adversary. For instance, the adversary has disabled all Internet-based communication. The adversary even actively monitors wireless communication. Protocol designers have identified the following threats [BRIAR] for similar circumstances: o The adversary can observe, block, delay, replay, and modify traffic on the underlying network. Thus, the microblogging service must ensure end-to-end security without relying on the security of the underlying network. o Wireless communication is regularly monitored. Responding to any wireless requests from a stranger is a direct threat to the user and extremely harmful. o Possession of encrypted electronic messages or encryption technology in general is extremely harmful to the smartphone owner. o The adversary has a limited ability to compromise smartphones or other participating devices. If a device is compromised, the adversary can access any information held in the device's volatile memory or persistent storage. o The adversary can choose the data written to the microblogging layer by higher protocol layers. o The adversary cannot break standard cryptographic primitives, such as block ciphers and message-authentication codes. Pouwelse Expires April 25, 2013 [Page 9] Internet-Draft CensorFree October 2012 Encryption is not a sufficient requirement of the friend-to-friend scenario, everything MUST be hidden. Possession of smartphones apps with encryption is already dangerous for the owner. 4.3.2. Scenario details and architectural requirements Reports from repressive regions indicate that USB sticks are commonly used to transport sensitive information. See for instance this extensive report on North-Korea [NKOREA]. In the friend-to-friend scenario a network of friends is trusted to transport news manually, by simply carrying it around. Smartphones with NFC capability or manual USB transfer are used to duplicate and move messages. Thus Alice delivers her fresh news message to Bob, which is later given manually to Charlie. As direct social connections are sparse and proximity of friends is not continuous, this scenario SHOULD facilitate usage of friends-of- friends or further removed social ties to relay news messages. This requires the development of a decentralized social network, for instance, with digital signatures of friendship certificates. In effect this would create a "decentralized social network", completely autonomous and owned by all participants. We assume Alice only has Bob in her friendlist and Bob only has Charlie in his friendlist. An OPTIONAL feature is that the smartphone apps running on the smartphone Alice and Charlie detect that they have friendship path through Bob. Fresh news is thus exchanged. The interception of a single smartphone MUST NOT expose the app itself, any friend list or worst: the entire social network. We assume Alice is placing herself in danger with electronic tools for "subversive activities against the democratic republic". Information hiding techniques are essential or even life-critical. Possibly based on Zero-Knowledge Proof (ZKP) protocols [ZEROKNOW]. The smartphone app MUST pose as a harmless entertainment feature of a smartphone or use another mechanism to become a "stealth app". This scenario requires modification and enhancement based on real- world experience from human rights activist [EGYPTSTUDY]. 4.4. Transmorph ability Prior scenarios expanded the threat model. This and the following scenarios are focused on the social media context. News is created in a region without freedom and then needs to travel to the outside world. We refer to this simply as the freedom/non-freedom border. Different transport protocols, dynamics and different solutions are needed on the two sides of this border. Pouwelse Expires April 25, 2013 [Page 10] Internet-Draft CensorFree October 2012 We now expand the friend-to-friend scenario with a transmorph ability, the ability of news to cross the freedom/non-freedom border. Alice is a well known blogger in an region with extreme censorship. Her identity on Twitter has millions of followers. However, she has no direct ability to reach a Twitter.com server or Internet in general. We assume Alice only has Bob in her friendlist and Bob only has Charlie in his friendlist. Charlie is able to smuggle a collection of messages out of the country. The messages originating from Alice should be transmorphed into a series of Twitter post belonging to her. The identities used in Twitter are highly identifiable labels, with a certain trust level. This hard identity with millions of followers is a stark contrasts with anonymity. Current anti-censorship technology lacks the ability to first have stealth encrypted transport of news, cross the freedom/non-freedom border and then transmorph this news into a public accessible form with a highly identifiable label. 4.5. A single global conversation Existing technologies, such as [TOR] in combination with XMPP or the Orbot smartphone app facilitate protected point-to-point communication. However, a desired scenario is to facilitate more current the Twitter-like social media practices, best typified as a "global conversation". Furthermore, current social media revolves around video-rich, real- time interaction with groups, hashtag-based discovery and social networking. All of these aspects are not offered or are incompatible with current-generation of privacy enhancing technology. More knowledge is needed about reputation models in news reporting and information flows. In the current microblogging age, does the number of real-person followers be seen as your reputation? Do several news sources of moderate reputation which report the same news story yield together an increased reputation score? This work should combine privacy enhancement with microblogging. 4.6. Spammers and hoaxes This final scenario is focused on spam. All technology addressing one of the above scenarios MUST also have the capability to deal with spam. Unfortunately, this ability to deal with spam is in conflict with simplicity. Alice and Bob are exchanging the fresh messages from their social Pouwelse Expires April 25, 2013 [Page 11] Internet-Draft CensorFree October 2012 network (similar to Internet-free or Friends-only). Eve is actively trying to disrupt the system by injecting news channels with a mix of genuine news, obviously fake messages (consuming valuable system resources and user attention) and hoaxes. These falsehoods made to masquerade as truth result in erosion of overall trust in the system. Systems SHOULD offer capabilities to report spam, mechanisms for fact validation and reputations of (pseudo) identities. 5. Design principles: simplicity and prior success Designing and crafting software which is completely self-organizing has clear limits [CAPLIMIT] and requires a certain level of expertise [LEVELS]. In order to avoid repeating mistakes from the past, this document aims to base itA's design principles on existing new media successes. For microblogging this means following market leading solutions and enhance them with censorship resilience. We recognize the following success factors: Simplicity, Real-time responsiveness, Near-effortless news creation, News items are bundled in channels, combine public broadcasting and person-to-person private messaging, following a channel is single direction, more followers yields more visibility, keyword search with push of updates and ability to deal with spam. 6. Background rant: lack of coordination and fragmentation Computers communicating on equal footing has been part of the IETF standards for many decades. Recently several loosely connected standard initiated around explicitly driven by the P2P paradigm for applications such as Internet telephony video streaming. An essential problem in this domain is the lack of coordination and standard setting for P2P technology. A large part of the innovation around P2P seems to happen in single-person Open Source projects and small groups which lack the engineering capacity to make generic, re- usable and documented components. Given their running code-driven nature, money and time is not available for attending standards- setting meetings, writing formal specifications and defining quality control testing suites. Profit-driven organizations should have the resources to overcome these resource shortage issues. However, due to the dynamic, disruptive and litigious nature of P2P few examples exist of companies which are capable of supporting an IETF standard setting activity for several years. As presented during IETF 81 area directorate, there is "not a clear long-term architecture yet for you to build actual classes of P2P applications using IETF technologies". Forming an overlay is hard and scalable privacy-preserving unstructured search solutions are only barely out of the scientific research community. Pouwelse Expires April 25, 2013 [Page 12] Internet-Draft CensorFree October 2012 From the above we conclude that a key obstacle to the success of this proposal is implementation and uptake. A draft document, active community and reference implementation ideally evolve together over time. To overcome this issue a continuous incremental improvement approach is advised. The preferred way is incremental development of single a reference implementation, based on free software. 7. Current running code and related work DISCLAIMER: this section needs significant expansion and listing of projects with running code and self-organization. Several Open Source projects have running code and partially implemented the above four scenarios. We will briefly list them here. [TOR] A free software implementation of second-generation onion routing, a system enabling its users to communicate anonymously on the Internet. This flagship project has boosted online anonymity for over a decade and the key example for the cat and mouse dynamics. The Orbot project provides an Android implementation of Tor. Due to the usage of the client server/model, exit node principle plus lack of reputations this architecture is not compatible with our scenarios. [DIASPORA] A free personal web server that implements a distributed social networking service. This partially operational system is based on the client/server model and not compatible with our ad-hoc scenarios. [BRIAR] Briar is a secure news and discussion system designed to be used by journalists, activists and civil society groups in authoritarian countries. Briar differs from existing circumvention tools and mesh networks in three significant ways: needs no external infrastructure, can operate over any mixture of available media and builds on social relationships. The aims of this project are similar to our scenarios, but this project lacks running code and has few active developers. [BUBBLE] DTN researchers have simulated closely related scenarios. Dissemination in the Arab Spring scenario is likely to involve an explicit copy between people who trust each other, referred to as social-based forwarding in this study. [TWIMIGHT] The Twimight project by ETH-Zurich university shows that decentralized microblogging already exists. Researchers developed an Android application that uses Twitter servers in normal conditions, but switches to a Bluetooth-based disaster mode when Internet Pouwelse Expires April 25, 2013 [Page 13] Internet-Draft CensorFree October 2012 connectivity is lost. [MUSUBI] The Musubi smartphone app represents another key, censorship-free, technology advancement. Developed by Stanford University, it offers instant messaging service and media sharing capabilities similar to WhatsApp, Ping, and Blackberry Messenger. What makes it unique is that all data and processing resides on the smartphones, not in the cloud. This decentralization removes the need for central processing and provides significant decoupling from the underlying infrastructure. Exchange of cryptographic keys is integrated in the friending process--Musubi essentially builds a decentralized social graph. Unfortunately, Musubi is also limited-- all data transfers go through central servers, as it lacks NAT- traversal capability. [TRIBLER] DISCLAIMER2: this project is coordinated by the author. This project has created Open Source firmware for a Samsung Internet- connected television which gives it the ability to find, share and stream news videos within a fully self-organizing overlay; operated only by remote control [REBELLIONTV]. It is also available as generic zero-server file sharing software for the PC which has been installed by 1.2 million users. It uses the Dispersy elastic database for providing: keyword search, content discovery, content voting and spam prevention using crowd sourcing [DISPERSY]. For swarm-based streaming and generic message transport it uses the IETF protocol developed within the PPSP working group, called Libswift [LIBSWIFT]. All this code is created by a single team and specifically designed to facilitate evolution into the prior described scenarios. An Libswift demo streaming app is available on the Android market. 8. Open issues Deliverables planned and issues which need to be addressed. TODO: ADD REF Privacy definition: http://tools.ietf.org/html/draft-iab-privacy-terminology-01 TODO: REF http://www.ietf.org/id/draft-iab-privacy-considerations-03.txt TODO: http://datatracker.ietf.org/doc/search/ P2P TODO: http://datatracker.ietf.org/doc/rfc4981/ SEARCH survey TODO: https://datatracker.ietf.org/doc/draft-ietf-p2psip-reload/ Pouwelse Expires April 25, 2013 [Page 14] Internet-Draft CensorFree October 2012 8.1. Use cases and threat model 8.2. System components, definitions and system architecture 8.3. Current technology and gap 8.4. Detailed system design and protocol specification 9. Security Considerations tbd. 10. IANA Considerations tbd. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 11.2. Informative References [RFC4787] Audet, F. and C. Jennings, "Network Address Translation (NAT) Behavioral Requirements for Unicast UDP", BCP 127, RFC 4787, January 2007. [RFC4838] Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst, R., Scott, K., Fall, K., and H. Weiss, "Delay- Tolerant Networking Architecture", RFC 4838, April 2007. 11.3. URL References [YOUTH] http://www.nytimes.com/2009/01/25/magazine/ 25bloggers-t.html, "Revolution, Facebook-Style". [FORCEDLOGIN] http://online.wsj.com/article/ SB125978649644673331.html, "Iranian Crackdown Goes Global". [NKOREA] http://audiencescapes.org/sites/default/files/ Report_Summary_Quiet_Opening_North% 20Korea_InterMedia.pdf, "A QUIET OPENING: NORTH KOREANS IN A CHANGING MEDIA ENVIRONMENT". Pouwelse Expires April 25, 2013 [Page 15] Internet-Draft CensorFree October 2012 [EGYPTSTUDY] http://conferences.sigcomm.org/imc/2011/docs/p1.pdf, "Analysis of country-wide internet outages caused by censorship". [OPENMICRO] http://xmpp.org/extensions/xep-0277.html, "XEP-0277: Microblogging over XMPP". [DATING] http://www.washingtonpost.com/wp-dyn/content/article/ 2006/08/05/AR2006080500930.html, "Saudi Youth Use Cellphone Savvy To Outwit the Sentries of Romance". [TREND] http://www.google.com/trends/?q=bluetooth+transfer, "Google Trends query". [BOOTSTRAP] http://grothoff.org/christian/dasp2p.pdf, "Bootstrapping Peer-to-Peer Networks". [ZEROKNOW] http://www.cse.ust.hk/~liu/luli/PT_Trans_final.pdf, "Pseudo trust: Zero-knowledge based authentication in anonymous peer-to-peer protocols". [CAPLIMIT] http://doi.ieeecomputersociety.org/10.1109/MC.2012.54, "The CAP Theorem's Growing Impact". [LEVELS] http://blog.incubaid.com/2012/03/28/ the-game-of-distributed-systems-programming-which- level-are-you/, "The Game of Distributed Systems Programming. Which Level Are You?". [TOR] http://www.torproject.org, "Tor Project: Anonymity Online". [DIASPORA] http://diasporaproject.org/, "Diaspora is a fun and creative community that puts you in control.". [BRIAR] https://fulpool.org/btp.pdf, "Secure communication over diverse transports". [BUBBLE] http://dx.doi.org/10.1109/TMC.2010.246, "BUBBLE Rap: Social-Based Forwarding in Delay-Tolerant Networks". [TWIMIGHT] http://dl.acm.org/citation.cfm?id=2159576.2159601, "Twitter in disaster mode: smart probing for opportunistic peers". [MUSUBI] http://dl.acm.org/citation.cfm?id=2187866, "Musubi: disintermediated interactive social feeds for mobile devices". Pouwelse Expires April 25, 2013 [Page 16] Internet-Draft CensorFree October 2012 [TRIBLER] http://dl.acm.org/citation.cfm?id=2206767, "Tribler: P2P search, share and stream". [REBELLIONTV] http://www.tribler.org/trac/wiki/SwiftTV, "RebellionTV a.k.a. Libswift on a television project". [DISPERSY] www.frayja.com/pub/ dispersypaper2012.pdf:donotdistribute, "Dispersy elastic database". [LIBSWIFT] http://www.libswift.org, "IETF PPSP streaming protocol implementation". Author's Address Johan Pouwelse (editor) Delft University of Technology Mekelweg 4 Delft The Netherlands Phone: +31 15 278 2539 EMail: J.A.pouwelse@tudelft.nl Pouwelse Expires April 25, 2013 [Page 17]