IT’S NOT MAGIC forcalls video Interfaces andprotocols Juliana Guerra la_jes cacu Martu Isla

1 It’s not magic, Interfaces and protocols for video calls This publicationpossible was made withthe support 19. of Article Edited by Vladimir Garay. English Translation by Cruz. Selene Cover and publication by design Constanza Figueroa. Común Cooperativa). Written by Martu Isla, Juliana Guerra, (Sursiendo), la_jes (Tierra cacu ://creativecommons.org/licenses/by/4.0/deed.en International BY4.0): (CC Licence This work is available under aCreativeCommons Attribution 4.0

2 It’s not magic, Interfaces and protocols for video calls information exchange was proposed to becomeWorld the Wide Web In 1989,at European the Center for Nuclear Research (CERN)atool for collaboration and But for now, let’s go back to promise the of internet. the ability to ‘navigate’. access: once we can connect, our technical, linguistic, and determine our also cultural skills make connection the and technologies the But that devices. is this only run one dimension of available and how robust it on depends is, inturn which materials also the that are to used sive to connect and connections are slower. Hence, it relies on how much isinfrastructure The cost depends the infrastructure; on for instance,poorer in countries it is more- expen broadband, cost the because is not also same. the even if it is not same the as a computer, and it is not same the to connect to fixed or mobile access to internet? the Perhaps, it means to have access to atablet adevice, or phone, acell buttries, internally, also urban contexts. and between rural But what it does mean to get gap ininternet access, inits multiple dimensions. The figures between coun- unequal are very regions such as and America Latin of there Caribbean, evidence the persistent the was also In addition to imminent the crisis generated by suspension the of economic in activities, veillance remained alarge inplace, while of part population the was forced into confinement. ments. In many cities around world, the only “essential” the ofactivities care, cleaning and sur internet was built. From one moment to next, the much of world the turned to environ digital - As aresult of pandemic, Covid-19 the inrecent months we have promise the faced on with i. Inisolation,can we stayclose? 1 days, we not only connect to work, or learn doadministrative procedures, our emotions and allowed connection skyrocketed to some internet level the of services, connections. Nowa- of information, digital development the while of in mobile 3Gtechnology telephony, which Almost ten years later, transmission the of over video internet the greatly traffic increased the continued until today. it was entering government offices, companies and homes, in anexpansive thatprocess has tween 1993and 1994,it an began to be attractive product for market the and little by little, supporting different platforms and extensibledata to new formats. Withthatbe- purpose, scientific community. It was conceived as auniversal interconnected information system, From Web the beginning the to was designed organize and streamline work the of aspecific mation was connected inan unlimited way, not on afixed based hierarchical system. The proposal consisted of adistributed system, legiblehypertext forpeople whereand infor protocol HTTP the (Hypertext Transfer Protocol) that we today use to navigate internet. the https://www.w3.org/History/1989/proposal.html Tim Berners-Lee. CERN. 1989-1990. Information Management: A Proposal. 1 , and materialized in

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3 It’s not magic, Interfaces and protocols for video calls embodying multiple identities and realities. This is the recognized by Feminist Principles ital environments we have and experiences initiate relationships we inwhich are necessarily connection to fixed or mobile broadband, inconfinementbecome evident it has how indig- Nonetheless, or figures the beyond access andthe to goods on digital services, quality of teroperability as well as data and privacy of security. services, it attention the calls to need guarantee the information access to medical digitized and in- mobile broadband connection In speed. addition, for provision the of online services, health entertainment it to expand is first fixed necessary services, broadband coverage and improve region, including access to education health, and work, as well as to shopping, banking and ECLAC says that inorder to guarantee effectiveparticipation environments indigital the in works operating region, in the although potential the for connectivity remains quite limited. This meant an increasetraffic in andgreater demands oncapacity and resilience the for net- 157%. merce and services delivery of use the teleworking solutionsically: increased 324%,distance learning 62%,and E-com- broadband communication and America inLatin increased dramat Caribbean the - services on being able to use these services optimally? on able being services to these use and conferencingcess calls to video video is universal. In other words, what it does depends we want to understand how communication this is technically possible, and we wonder ifac- alternatives and characteristics their in terms of quality, or privacy, security document in this reasons the Beyond that us to lead prefer real-time audio and tools, or video commercial few or many people; inpresentations and workshops; insex. parties; inthe is often not fluent or understandable, inclass; eachmeetings insee other: with to we choose popularso inrecent months? Despite consuming many resources and that communication toolsdigital of intimes confinement, butwhy conferencingcalls and video video do became Collaborative editing, sharing, file and audio andvideo streaming areperhaps the most useful organization are necessarily mediated by internet technologies. feelings are connected. also Thus,pandemic, ina our circles trust,of affection, political and 2 to us. According satisfy to ECLAC the from many places we demanded and meeting, to strengthen there was internet social the the When physical the distancing measuresto began stop contagion the for Covid-19, curve ii. Contact Limitations https://repositorio.cepal.org/bitstream/handle/11362/45938/4/S2000550_es.pdf technologies to address the consequences of COVID-19. The Economic Commission for Latin America, ECLA. 2020. Universalizing access to digital 2 , during first the half the consumptionof 2020, of

4 It’s not magic, Interfaces and protocols for video calls for Internet the 8 7 6 5 4 3 it was denounced its ability to “bypass browser settings and security remotely enable auser’s platformin the and misleading the discourse with itwhich wasAlready advertised. in 2019, As early as March, of criticisms aseries published beganto be regarding vulnerabilities the use of video calling platforms of calling use video and applications, some addressed to audiences, wide first the During months of 2020,different organizations published the guideslead to proper and subjected to different types violence. of users, since it is about connecting communities that have traditionallymarginalized been imperative to work expansion so of coverage is done with criteria of quality and dignity for require better to infrastructures optimally. function In point of for fact, reason, this it is rapidly advancing towards cutting-edge technologies, are which increasingly complex and profitable seeks industry solutions theto connect other half the of world’spopulation, it is- possibilityThe of accessingthe internet is crossed by multiple dimensionsthe while and unconditional, open, and meaningful equal” for access, especially women and queer people. day 2019,to 300million inApril inDecember 2020. option in businesses, State entities and schools. Thus, it wentfrom participants 10 million per downthebecame measures popular Zoommost conferencing beganto video effect, take interface,friendly guaranteeing while astable transmission of audio and video. As early- lock to position itself as a competition against Apple , or , offering asimple and Zoom’s is paradigmatic. case This company located in Silicon Valley, sincetrying 2013was designspolicies, and settings, to respond to of needs the moment. the lysts turned eyesto their most the popular platforms, and many of had to update these their critical groupscritical such as journalists, https://blog.zoom.us/90-day-security-plan-progress-report-april-22/ Data publishedon the . Available on:https://blog.zoom.us/a-message-to-our-users/ y conferencing-tools https://www.frontlinedefenders.org/es/resource-publication/guide-secure-group-chat-and- Guide onsafe tools for conferences andgroup chats educators/ https://cdt.org/insights/protecting-students-in-virtual-classrooms-considerations-for- Protecting Students in Virtual Classrooms: Considerations for Educators. https://freedom.press/training/blog/videoconferencing-tools/ conferencingright video Choosing the for tool job. the https://videoconferencing.guide/, amongother sources. InSpanish,and for Latin America. In English https://foundation.mozilla.org/en/privacynotincluded/categories/video-call-apps/ y on critical Internet-related rights. 2014-2015. https://feministinternet.org/en Feminist Principles of the Internet. Statements that offer agender andsexual rights perspective 3 , which for, which years several have for called “universal, acceptable, affordable, 5 school teachers school 6 or activists 8

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5 It’s not magic, Interfaces and protocols for video calls to Facebook someone when to notify application, opened the a vulnerability waiting inthe room of ameeting. desktop client or for infocus more than 30seconds. for attention the tracking allowed; which hostess the ifany see attendees donot have the encryption”, RTP (Real-Time Transport Protocol) standard, traffic and media was andde- encrypted all implementedZoom its own transport protocol, with some modifications overthe existing Alerts were forraised Alerts also so-called the web camera without knowledge the or consent of user” the 19 18 17 16 15 14 13 12 11 10 9 As explained by The Intercept the endat of March, ones like , Hotmail or Yahoo. with accounts subscribed who differentthose inother servers than the popular most nisms implemented inmacOS, end (E2E)but only chat, the that is, text . According to report the by CitizenLab, on awebsite The iscommunication encrypted. that has HTTPS was end-to-not encrypted connection client the between and platform the same inthe was way encrypted, as navigation crypto-a-quick-look-at-the-confidentiality-of-zoom-meetings/ Move Fast andRoll Your OwnCrypto... https://citizenlab.ca/2020/04/move-fast-roll-your-own- https://theintercept.com/2020/03/31/zoom-meeting-encryption/ Zoom Meetings Aren’t End-to-End Encrypted, DespiteMisleadingMarketing https://citizenlab.ca/2020/04/zooms-waiting-room-vulnerability/ Zoom’sWaiting Room Vulnerability https://techcrunch.com/2020/04/03/zoom-calls-routed-china/ Zoom admitssomecalls were routed through Chinabymistake confidentiality-of-zoom-meetings/ https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the- Move Fast andRoll Your OwnCrypto. A QuickLook at the Confidentiality of Zoom Meetings https://twitter.com/c1truz_/status/1244737675191619584 https://www.vice.com/en_us/article/k7e95m/zoom-leaking-email-addresses-photos Zoom isLeaking Peoples’ Email Addresses andPhotos to Strangers facebook source. https://www.vice.com/en_us/article/z3b745/zoom-removes-code-that-sends-data-to- you-dont-have-a-facebook-account. This feature was quicklyremoved according to the same https://www.vice.com/en_us/article/k7e599/zoom-ios-app-sends-data-to-facebook-even-if- Zoom iOS App SendsData to Facebook Even if You Don’t Have aFacebook Account https://techcrunch.com/2020/03/17/zoombombing/ Beware of ‘ZoomBombing’: screensharing filth to video calls youre-not-paying-attention https://www.vice.com/en_us/article/qjdnmm/working-from-home-zoom-tells-your-boss-if- Working From Home? Zoom Tells Your BossIf You’re Not Paying Attention ftc-. FilesComplaint with FTC aboutZoom https://epic.org/2019/07/epic-files-complaint-with- 15 its routing alternatives, since inChina pandemic the began, using servers 14 the implementation the of “what company the end-to-end calls 13 Then, cameit analysis the on pre-installation mecha- Zoom Bombing Zoom

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6 It’s not magic, Interfaces and protocols for video calls some organizations shared recommendations for remote work Regarding difficulties risksand associated the increasingwith use digitalplatforms, of free by greats the of internet? the zations, movements, groups and individuals cannot who afford offered accessservices the to and are they ones the dominate who services market the today. But what about organi the - nies that answered best to institutional the demand for and calling conferencing video resources from end customers. toogies integrate and video guarantee communication, whichnot does requireso many text messaging over internet. the years, the Over it implementing has been different technol- is an open source project that in 2003 began developing a desktop application for voice and and privacy. (Microsoft) and continue (Cisco) Webex in termsto ofoffer betterquality, service a stability However, of payment the and this other platforms services such as Teams Meet (Google), Since its is open, it code is possible to your install own instances and many organizations 24 23 22 21 20 privacy ofprivacy its users and inApril launched a90-day plan to repair errors and vulnerabilities. In order brief to onit be Zoom, is worth saying that company the made acommitment to the considered within weak existing standards. as very distributed by platform’s the to participants, the mode, inECB(Electronic server codebook) with asingle AES-128key (Advancedcrypted Standard-128 Encryption bits), generated and cy-friendly tools, where Jitsicy-friendly Meet appeared as one of options best the for calls video User FAQ https://jitsi.org/user-faq/ blog/2020/05/que-esta-pasando-con-zoom/ coop/es/post/2020/node-167915/, ¿Qué estápasandocon Zoom? https://sursiendo.org/ novedades/2020/04/21/jitsi.html, Alternativas alasreuniones en vivo https://mayfirst. Vídeollamadas con Jitsi: laalternativa alasplataformas comerciales https://labekka.red/ recomendaciones-cuarentena/, amongothers. social/, Recomendaciones para unamejor experiencia enlíneahttps://ranchoelectronico.org/ recomendaciones-de-software-libre-para-usar-en-contexto-de-distanciamiento-fisico-pero-no- de distanciamiento físico (pero nosocial)https://www.vialibre.org.ar/2020/05/04/ seguras-tiempos-cuarentena, Recomendaciones desoftware libre para usar encontexto Conectadas yseguras en tiempos decuarentena https://blog.torproject.org/Conectadas- últimos meses,¿cuándo? making-privacy-and-security-luxury/ andGoogleMeet acabará con el‘gratis total’ delos Zoom isMaking Privacy andSecurityaLuxury https://foundation.mozilla.org/en/blog/zoom- done-whats-next-for-zoom/ CEO Report: 90DaysDone, What’s Next for Zoom https://blog.zoom.us/ceo-report-90-days- 21 Perhaps, that is why, with advance the of were pandemic, the these compa the - 24 22 based on and free based priva- 23 . Jitsi 20

7 It’s not magic, Interfaces and protocols for video calls video call is much call video more complex than setting up an instance. oras Amazon, Microsoft. Google It is important to mentionthat behindthe a infrastructure on of use the based intermediate owned by servers, large companies data inthe market such comparison of quality the of instances the and conditions privacy the operate, they inwhich formation - and about our own autonomy we when interact online –become urgent. is apriority for companies and governments,half” questions about sovereignty over our in- anwhen important of part our lives is spent on differentscreens, and “connectingthe other it with ahuge deals and technical commercial complex. Hence, of intimes pandemic, the with we which connect are increasingly and smaller information travels speeds, high at very But internet the is not acloud, it is not ethereal, it is material and solid. Although devices the as we hosted being have in“the to everything practically become used cloud.” operates,infrastructure to ensure that information this all remains available on internet, the process our data, at develop same the they time and standardize with the which rules the or media basis (search collaborative engines, social work platforms) but host and collect, also fewer and fewer companies, notwhich only develop tools with we which interact on a daily grown hasAlthough also base user the exponentially, internet the market is hands inthe of , since 2010most of traffic the the on internet audio and, years later, video. fibreOptical allowed not transporttheonly data,of transmissionthebut also of high-quality volumes of traffic, at lower costs compared to copper cables. exponential inthe growth of internet, the since it allowed transporting increasingly large worldwide; perhaps commercial the deployment of fiber opticsthe was most important fac- of internet the is changing and not only web the allowed it to become acommunication tool informationdigital and with them, amainly use. But between academic military logic the latein the internet the 1980s,when was atool to connect computers that could exchange possibilityThe of communicatingwith audio in andis a video real-time projectthat began ii. The gearsof infrastructure duringdid so pandemic. the 27 26 25 Clark, D. 2018. DesigninganInternet. Massachusetts Instituteof Technology. https://ladatano.partidopirata.com.ar/jitsimeter/ Jitsimeter ¿Qué instanciade Jitsi meconviene usar? optimizar-rendimiento-jitsi and publishedaseriesof recommendations to optimize itsperformance. https://maadix.net/es/ installing their own Meet Jitsi instances. https://maadix.net/es/instala-jitsi-meet-con-un-clic autonomy, securityandprivacy of itsusers. At the beginningof April, they had the service of Maadix isaninfrastructure provider that offers online work tools while guaranteeing the 27 25 If at internet the beginning the has allowed exchange the of For instance, inArgentina, it was developed Jitsimeter,

26 a

8 It’s not magic, Interfaces and protocols for video calls 29 28 like this: gies, communicate each other, work they also together using different communication technolo- er with TCP, have they responsible been for ensuring different that very types of applications We could say that network the (IP) is until today basis of the how internet the works. Togeth - tocols that govern operation the of Internet. the softwarefree options alternativeor infrastructures and understandbetter standards and pro- context ofbecause this inwhich need the puts us, we consider relevant to beyond look the and capacities, if we only want to hold ameeting that cannot done be in person. However, installs, maintains and networks? those accesses These questionscan exceed our interests Who wetime call? make owns avideo networks the through it which is transmitted? Who How much dowe know about information the about us that is captured and exchanged every layer runs the HTTP orlayer HTTPS HTTP the runs To access platform, differentlayers to communicateneed each other. the In application ware converts connection the information all into code. binary obtains device nected an IP(Internet Protocol) address that identifies it. Finally,the hard- (for example, and 80 for Then, port 443forthe HTTP at network HTTPS). layer, each con- Control Protocol), is which responsible for directing information the using differentports Your Computer Application class/msande91si/www-spr04/readings/week1/InternetWhitepaper.htm Shuler, R.2018. How Does the Internet Work? Standford University. https://web.stanford.edu/ comic guaranteed, as well as the identity of the siteandprivacy in the information. Bestexplained in this (Secure Sockets Layer) certificate, the integrity of the information shared with aspecific website is HTTPS addsalayer of encryption to the HTTP protocol. Through the generation of anSSL Hardware 1.2.3.4 TCP https://howhttps.works IP Basado enShuler, 2018.How R. Does the Internet Work? Standford University. Communication machines between 28 protocol; transport inthe one TCP the runs (Transport Internet 29 Another Computer Application Hardware 5.6.7.8 TCP IP

9 It’s not magic, Interfaces and protocols for video calls 30 application or anavigation one) and that, finally, are interested inestablishing communication. make agreatwill effort to differentiate them from users, who clientsinteract those call with video (a Although protocols technical usually refer to “clients” with power the as those to communicate, we and protocols call the video involved. applications. those use who Henceforth, we are going indepth throughout process the of a for develop who those and maintain browsers (such as or Chrome) and for people the is to easy implement. for applications develop who Both call those video (for example, Jitsi), is perhaps one of clearest the examples of how complex something very inits internal logic, WebRTC is standard the for real-time audio, and video data communications on web the and endpointsthe compatible with network the functioning. use. Protocols they technology and standards are common agreements to make work the at streaming real-time audio and video, web developers donot to need know details of the each In increasingly practice, while complex internet functionalities are developed, being such as structure is that most work happens at endpoints the and not on network. the by intermediate the routers, should which only at look IPinformation. the The idea layeredof works it end inthe nodes: is information by carried packets, the but it should not checked be over IP. But later, see as we will TCP is not only the transport protocol that TCP used. can be that happensIP is supposed ineverything to be on runs internet, the everything because analyze the informationanalyzeforward to the it. Although this principleisnot currently fulfilled, because the network is full of intermediaries who diverse Highly diverse Highly Based on Clark, D. 2018.Designing an Internet. Massachusetts Institute of Technology. standards Common Communication of model theinternet networks Cellular Games Ethernet Video Web Band Broad TCP IP WiFi Chat email area Wide- VoIP transport as packet The Internet technologies The supporting as experience The Internet 30

10 It’s not magic, Interfaces and protocols for video calls level, and Internet inthe Engineering Task Force 32 31 oped in the World inthe oped Wide Web Consortium can communicatenies, they with each other) project the on is open based standards, devel- To achieve interoperability different between browsersbelonging (even to different compa - create aprofile, install an application or download add-ons plug-ins or . isend that user she can establish acommunication from browser, their without having to guaranteeing quality and in communications. privacy benefit The that WebRTC offers to an is to allow transmission the inreal-time of audio, and video generic data browsers, between WebRTC is an open source project initially promoted in2011.Its by Google main objective Audio, video anddatainreal-time the data.the age is reliable. Unlike TCP, UDP not does offer any promise aboutthe reliability or order of is more important that information the is transmitted immediately, and not that eachpack- TCP for transportation but UDP (User Datagram Protocol) since, as it isit real-time media, areOnce devices the identified a WebRTCsession between peers is opened tion using internet. the other words, identifying themselves as end the points that establish will aP2P communica- Therefore,before starting anytransmission, it between devices. be In mustmade asignaling with backup that have servers sufficient resources to implement therequired functions. In WebRTC the model, browser the to have is expected ability the to work inconjunction web to world the of telecommunications. real-time communications to browser, the but about also bringing competences the of the ditionally telephone in digital whyThis is used service. WebRTC is not only about bringing or PSTN (Public Switched Telephone Network or Public Switched Telephone Network),- tra VoIP (voice over IP),clients SIP (Session Initiation Protocol or Session Initiation Protocol) application that integrated be can also with other existing communication systems, such as cation two or between more browsers, WebRTC implemented be can also inan independent otherOn the hand, evenifits main objective is to establish apeer-to-peer (P2P)communi- a home such device as computers, tablets or phones. cell have information high processing among speeds, other resources that normally donot have themselves, to because guarantee quality good real-time communications to it is necessary establish communication not This does peers. thatmean between browsers havethiscapacity Currently, browsers most the used support WebRTC, that have API is, they to necessary the Internet Engineering Task Force https://ietf.org/ WebRTC 1.0: Real-Time Communication Between Browsers https://www.w3.org/TR/webrtc/ 31 at API the (Application Programming Interface) 32 at protocols level. , that not does use

11 It’s not magic, Interfaces and protocols for video calls HTTP/WebSockets Based on https://www.tutorialspoint.com/webrtc/index.htm Both devices run aweb application from different servers. Web server device User’s using one or two intermediate but most servers, the common is model triangular the one. XMPP, or MQTT proprietary solutions sion Description Protocol). Meanwhile, different mechanisms such as SIP over , place through RTCPeerConnection, once session the profile createdbeen has with - SDP (Ses not have capacity the to interpret data the content. connectedtion browsers between does hasserver not defined, the since intermediary been for establishing aP2Pconnection. To that extent, amechanism for transport the of informa- This process is not part the of WebRTC standards, but as a preliminary it is stepnecessary rect transmission channel browsers, between aP2Pcommunication start will they then . naling process consists of searching for an intermediate that allows establishing server adi- to themselves identify asignal send URL.This the sig- via will agreedthe time, devices their To exemplify, suppose a group of people are about to a meeting start and, by connecting at 1. 34 33 SIP model SIP triangular Model trapezoidal Signaling Sobre losservidores queintervienen enunasesión WebRTC https://bloggeek.me/webrtc-server/ Signaling and video calling https://developer.mozilla.org/en- API Connection via Peer Media path path Signalling WEB device User’s Web server HTTP/WebSockets 34 can be used for used can be This signaling. processcanbe done index.htm server. Based on https://www.tutorialspoint.com/webrtc/ Both devices run asingle from the same device User’s 33

HTTP/WebSockets The information exchangetake will API Connection via Peer Media path Web server

WEB HTTP/WebSockets device User’s

12 It’s not magic, Interfaces and protocols for video calls 35 tream) and transmission 2)the of data, differentfrom audio (RTCDataChannel).andvideo capture, from browser, the of audio the and transmitted tracks that be video will (MediaS- (RTCPeerConnection) browsers, between WebRTCtwo API other fulfills maintasks:the 1) establishing,Besides managing and maintaining session the or P2Pcommunication channel Once the devices haveOnce devices the identified been amongthemselves, the API is executed, 2. WebRTCarchitecture the audiothe transferred. be and will video (for example, Jitsi the configuration orspecifically by Zoom), or of formats which in APIthe is implemented, inbrowser both (for example, Firefox or Chrome) and applications browsers.between The quality transmissionthe of that can users enjoy depends the wayon differentpieces fulfill tasks to establish the information media and flows inreal-time, directly Your browser WebRTC- Architecture Voice Engine ISAC/iLBC NetEQ forvoice Capture/Render Audio Noise Reduction Echo Canceler/ Session Management/Abstracsignaling(Session)

Based on https://webrtc.github.io/webrtc-org/architecture/ App #1 App Your web Your https://www.tutorialspoint.com/webrtc/webrtc_architecture.htm Overrideable bybrowsermakers (Edited byW3CWG) WebRTC C++API(PeerConnection)

WebRTC API architecture temporal devideo Almacenamiento App #2 App

Web API de imagen Mejoramiento Your web Your Video Capture

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App #3 App SRTP web Your TURN +ICE P2P STUN+ Network I/O Transport de señales Combinación developers Api forweb makers browser Api for 35 The web and their

13 It’s not magic, Interfaces and protocols for video calls needed; andneeded; statistics the report. maintenance and monitoring, as well as closing the of connection the once it is no longer openingthe of adata channel; identity the verification of connected peers; ability the with another to user; communicate with a WebRTC session through a phone call; and managing ICE next inthe section, protocols, aUDP connection described be will which Much of what is considered WebRTC is establishment inthe of P2P: processing the of SDP 2.1. RTCPeerConnection Moreover, parameters the for transport the of data inreal-time are established. 36 RTCPeerConnection Even success ifthe of aWebRTC transmission to depends alarge extent on participants’ the samethe time, sharing users or could listen be they several camera their to eachother. while synchronized,be same the might then user want to share camera their and screen at their .mkv. .ogg, rm, For transmission the inreal-time, objective the is that different the trackscan together incontainers, what for users are file formats or extensions as .avi,mpg, .mov, .mp4,. In general, for streams media stored to be or transmitted to encapsulate is necessary them with low latency), but care taking that transmission the is clear for participants. the eye or ear of aperson, inorder shortest tointhe and encode decode possible (that time is, decompress stream, media adigital discarding information all that is not perceptible to the In context the of WebRTC, is apiece of acodec softwarefunction is whose to compress and 2.4. Codecs WebSockets low and has latency. very a channel that comes from an existing RTCPeerConnection It object. same the uses API as negotiationcodec or stream synchronization. The maintask of RTCDataChannel is to create In addition to ,WebRTC P2Pmedia data send can bi-directionally also that not does require 2.3. RTCDataChannel is sharedmedia through RTCPeerConnection, the bypassing server. the is opened with session the description using an intermediate server, but once opened, the face can consist of multiple or video audio tracks, ifit is amulti-participant session. The flow one camera or microphone, or it permits not also to access any of MediaStream them. inter asking beforehand device, the user the ifallows access; this and, there incase is more than The MediaStreamallows capturing, from browser,the local bothcamera and microphone of 2.2. MediaStream https://developer.mozilla.org/es/docs/Web/API/RTCPeerConnection 36 the connection the -

14 It’s not magic, Interfaces and protocols for video calls Google, has implementedGoogle, on same the used YouTube, VP9 codec, the owned also by Google. not just developed with WebRTC the those standard. Currently, Chrome browser, owned by andby is an Google open source, and that is why it adopted has been indifferent applications, Today, standard video the that is most inWebRTC, widely used VP8+H264,was developed information. original the all inWebRTC, used otherthe codecs are characterized by having loss, that donot is, they retain plications such as VoIP, conferencing video and voice chat in games, among others. This, like interoperability, according to RFC7875. , according to RFC7874, haveAlthough codecs evolved, most the audio widely used standard inWebRTC today is connection quality, 39 38 codec negotiationcodec that is done through SDP. to have a better transmission quality using minimum the amount of resources, as well as the MediaStream synchronizes multiple audio and video tracks (MediaStreamTrack). Based on https://hpbn.co/webrtc/ Additional WebRTC Audio Codecs for Interoperability https://tools.ietf.org/html/rfc7875 WebRTC Audio Codec andProcessing Requirements https://tools.ietf.org/html/rfc7874 37 the codec configuration codec the the in browsers theand in applicationsallows facingMode:user MediaStreamTrack width:1024 (Video) ... 38

15 It’s not magic, Interfaces and protocols for video calls WebRTC standard. developed to supportbeen real-time audio and video, under conditions the defined the by transmission,video among other functionalities. For extensions reason, this necessary have before its invention there were for infrastructures IPtelephony and unidirectional audio and transport layers, have which developed for not specifically been WebRTC, that due the fact to To make process this possible, different protocols are theused at application as well as at to transmission- media it enables also opening adata channel browsers. between browsersbetween information (codecs, on bandwidth and -inparallel IPaddresses). Besides connection is established, it allows exchange the and agreement of communication details each browser has, and to attach broadcasted. tracks to media the be Furthermore, once the (for instance, there two can of be and video four of audio) capabilities with best the that users, to stream. amedia start In other words, to recognize and to synchronize tracks the each of browsers the within asession, that be with authorization the will of respective their far,So we have WebRTC the reviewed API, allows which one to capture audio and in video Protocols3. for WebRTC of service, bearing inmind bearing that transportof over service, UDP is not reliable TCP), (unlike but is based nel SCTPtransport the uses protocol to control flow and congestion, and measurethe quality Parallel to transmission, media a data channel browsers between opened. This be chan will - generated and signaling channel the to reach is used peers browser with RTCPeerConnection the Once object. that process is complete, SDP offer is is possible, it because processes connection the establishment requests that registers each UDP, but later, see as we will ICE is process the by interaction this which browsers between With NAT, STUN and TURNprotocols, aP2Pconnection is established and maintained over Despite WebRTC over runs UDP the transport protocol, pre-signaling is done over TCP. Transport Layer Network Layer Based on WebRTC Tutorial, IETF 100.2017.https://youtu.be/viZC1G4tmVM HTTP WebSocket TLS TCP WebRTC protocols SRTP DTLS IP UDP SDP . SCTP ICE DTLS STUN UDP TURN

16 It’s not magic, Interfaces and protocols for video calls flowsthrough the internet infrastructure. That’s the job of application protocols. must developed browser in the be that allow opening and maintaining stable communication velopment and implementation. From point atechnical of view, implies this that capabilities perhaps that is why gamer the community is one the that has contributed most the to its de- from web the browser. For enables users, this to of access, and learn type system, this use and One of biggest the benefitsthat WebRTC offers that is all management ofa livestream is done 3.1. Application Layer throughout process, the to guarantee and of privacy security the transmitted the information. effort on best the 40 that two devices between are NAT behind routers.software The must incorporate a STUN In context the of WebRTC, information this to configure is used an UDP communication through NAT. public IPaddress, of type NAT the it is inand internet the port associated port with local the works under client/server the model, since it allows NAT clients (like abrowser) to find its This protocolallows know a to user the public IPaddresswhenever surfing the internet. It STUN -Session Traversal Utilities for NAT For reasons, security today many home routers as firewalls and serve NAT devices. Using NAT asingle port, translate will aprivate IPaddress into apublic one. throughout router the managed by that ISP we can access apublic IPaddress and navigate. When(IPv4). we connect, ourmakes arequest device provider to internet the (ISP); service NAT exists to manage limited the number of IPaddresses version inthe 4of IPprotocol 3.1.1. NAT -Network Address Translation wants to traffic. the send That’s used what TURN is for. private IPaddress to apublic one is conditioned by destination the IPaddress to one which NAT configuration not does supportthat protocol, that due the fact to translationthe from a internalbetween and and is devices, external this done through STUN, but symmetric the For interaction the establishment through ICE, to and send it receive is necessary packets municate private of local devices the the network devices. with external the tion, there are different types of NAT configurations, depending the on restrictions to com- Clark,D. 2018. ibid,p. 25. principle. Additionally, TLS,DTLS the and SRTP protocols are presented RFC 2663https://tools.ietf.org/html/rfc2663 RFC 5389https://tools.ietf.org/html/rfc5389 40 In addi-

17 It’s not magic, Interfaces and protocols for video calls 3478 over UDP. ferent of types NAT handle incoming UDP packets, although it is usually done through port opened by has been port which NAT to allow incoming traffic the to client’s network. Dif- client that requestssends to a STUN server, informswhich client the of its public IP and 41 of use the TURN.Toport optimize resources, COTURN today most connections have protections, security nearly so any WebRTC must sup service - Even process though this is more resource intensive and therefore only as alast resort used, and connects to destination the that server on its relaying behalf, packets. the messages two clients. between For client the purpose, this must connect to TURNserver the around NAT. to TURNis designed avoid restrictions to relay these and athird uses server all When arouter NAT symmetric uses or system,traversal afirewall the protocol uses repeaters 3.1.2. TURN - Traversal Using Relays around NAT that as TURNand act STUN at same the time.

Free opensource implementation of TURN andSTUNServer https://github.com/coturn/coturn Based on https://developer.mozilla.org/es/docs/Web/API/WebRTC_API An STUN server discovers thepublicAn STUN IPof server theclient Peer B Peer A 209.141.55.130:3255 you are: who amI? RFC 5766https://tools.ietf.org/html/rfc5766 server STUN 41 servers have developed, been servers also

18 It’s not magic, Interfaces and protocols for video calls alive and ifabetter to performance see delivered can be through an alternate route. continues STUN to requests issue periodic to other the peer. This is theto connection keep STUN, and as alast TURNis resort. used Afterthe connection is established,the ICE agent forperformed candidate entities: IPaddresses are local checked first,then public IPs via The ICE agent automaticallysorts and prioritizesthe orderwhich connection in checks are to establish connection. the RTCPeerConnection is marked as or failed that connection the to aTURNrelay falls server a path for opened. If be P2P connection the will candidates the fail, it can happen that the otherthe entity must acknowledge with STUN asuccessful response. If is this completed, The runsprocess nearlythe in followingthe ICE way: agentsends a joinSTUN requestthat conditions ifit to can see reach other the entity. titles availableport to aremote entity. With ICE the this, agent connectivity the can verify offerthat the set in is RTCPeerConnection contains object alist candidatesof IP, as well as to connect with others, identifying areliable route to doso. The connectivity The protocol forthe establishment of interactive connectivity is a processthat facilitates a 3.1.3. ICE-Interactive Connectivity Establishment Based on https://developer.mozilla.org/es/docs/Web/API/WebRTC_API A TURN server solves the symmetric NAT solves thesymmetric A TURNserver restriction server TURN Peer B Peer A Behind symmetricNAT 209.141.55.130:3255 you are:

who ami? RFC 5245https://tools.ietf.org/html/rfc5245 server STUN

19 It’s not magic, Interfaces and protocols for video calls is data flow. connection over UDP ICE starts. care takes of Communication this. last as long will as there that madeconnection this control possibleserver loses over session, the and direct P2P the createdbe for and calling the receiving entity. When entities both are already recognized, the As as RTCPeerConnection the soon created, has been SDP offer/answer text to string needs are. with use, what bandwidth to linked can connection the be and IPcandidates the who to connect Its is function not to deliver content, but to enter into anegotiation toto which define codecs of eachone of entities the that participate will to establish parameters the to open asession. This protocolallows negotiatingthe under offer/answer by model recognizing capabilities the Transport Protocol). define howthatthe later media to encode transmittedwill be using SRTPReal-Time (Secure transmission, and within framework the of WebRTC it together is used with SIP, mainly to SDP is responsible for describing asession profile. This protocol widely is used for real-time following way: of with attributes. aseries A session is described attribute Each is on aline, illustrated in the tion control and management innetwork traffic, in orderguarantee to quality service. of In context the of WebRTC, transport the functionsthe layer congesof signaling, fulfills - 3.2.Transport layer 3.1.4. SDP -SessionDescription Protocol Zero or Zero more descriptions media a=*(zero or more lines of session attributes) key) k=*(encryption zone z=*(time settings) One or more lines of below description time “t (See =”and “r =”) b=*(zero or more lines with bandwidth information) information) c=*(login p=*(telephone number) e=*(email) u=*(URIdescription i=*(session information) s=(session name) o=(source and session identifier) v=(protocol version) RFC 4566https://tools.ietf.org/html/rfc4566

20 It’s not magic, Interfaces and protocols for video calls protocol developed. began to be late network 1970sthe (IP)layer was separated from transport the (TCP) layer and UDP the sending packets, what was not for useful, example for audio transmission. Thatwhy is the in IP were same the internet basic protocol. But, given its complexity, TCP often had adelay in allows data from different applicationstransportedbe to simultaneously. Initially, TCP and arrive at destination, their inorder and without errors. In addition, system, with port the it For transport, TCP organizes and eachbyte sends individually, ensuring that of all them over run TCP.connecting to aserver) and received. Applications such as web, the email, FTP(for sharing) file or SSH (for remotely end-to-end, and for that reason it employs averification system,eachpackettime a sent is communicated.to be In addition, it that so is designed information is transmitted reliably Thatwhy is TCP is connection-oriented:run, to it requires prior synchronization parts the of nication field, systems is means, military inthe in an environment susceptiblebe to attacked. This protocol is as theold internet.as needs the It was of designed to specific meet commu - 3.2.1. TCP – Transport Control Protocol overruns TCP. support areal-time communications that on runs top service of from web, the inturn which are(which normally encapsulated inUDP), protocols the that intervene inWebRTC must Although awhole work area layer developed inthis has been transport inreal-time media 42 SRTP protocol is since mandatory. encryption including IP telephony and television systems, among other systems. WebRTC standard uses 1996, RTP development the has served of communication and transmission media systems, RTP (Real-Time Transport Protocol) packets travel encapsulated inUDP. Firstly published in order packages the inwhich arrive at destination, their nor arrive. ifthey not with individual bytes.allows This onebe moreto because agile, notit does guaranteethe As its name suggests, UDP works with messages, that is, with datagrams or packets of bytes, mation for packet routing) work over UDP, since it requires aminimum of network the to run. resolution), DHCP (for assigning private networks) IPaddresses inlocal or RIP(with infor or establishment of aconnection Application to run. protocols such as DNS (for domain name publishedOriginally in 1980, UDP is transaction-oriented, it means that it not does require pri- 3.2.2. UDP –User Datagram Protocol Clark, D. 2018. ibid. 42 RFC 793https://tools.ietf.org/html/rfc793 RFC 768https://tools.ietf.org/html/rfc768 -

21 It’s not magic, Interfaces and protocols for video calls UDP, what provides transport through NAT once achannel opened through has ICE. been through aDTLS tunnel to guarantee information confidentiality.runs Likewise, DTLS over channel SCTP to uses queue management and congestion control, but here SCTP connects Parallel to transmission, P2Pmedia the WebRTC opens adata channel browsers. between This tion and cookie amandatory verificationthetag in sent header eachof packet. greater incommunication security with afour-way handshake that includes an authentica- that sameso the port, communication is not blocked ifthere is any failure.). Guaranteeing multaneous connection networks) to several and multistreaming data streams (several with control and improve fault tolerance sending when packets, offering multihoming support (si- It is about amuch less complex protocol than TCP and despite that, it allows congestion transportation more efficient. guarantee ofinformation, arrival the the all allowing it sent to be indisorder, what makes packet sequencing, like TCP. But similarly to UDP, it message uses delimiters, not bytes, to native to TCP and UDP, as it is connection-oriented, provides reliability, flow control, and phone networks (PSTN) and was first published in 2000. transportthe At layer, it is alteran directlySCTP runs over IP, it was developed for transport signaling inpublic switched tele- 3.2.3. SCTP -Stream Control Transmission Protocol a permanent problem. At IETF, aWorking Group was formed to improve inRTP privacy The development of extensions and protocols forthe implementation of WebRTC been has in connection establishment. with access to information the servers) case (in this of participants the necessarily action take fortrust, develop who those applications and for since them, third also use who parties those capacities and flows customersby end in browsers Thisand devices. supposes an exercise of or signaling process fell outside standard. the However, it on exposure is the based of local Even ifWebRTC is careful insetting and up for privacy security streaming pri the media, - to camera the and microphone. and SRTP protocols and requires browsers to implement access authorization management is amandatorycryption feature inWebRTC; and therefore, mainly is on based DTLS security Taking installed. to be into account of risks associated the with ease access this for users, en- standardthe proposes that it on runs web the and not does require any application or WebRTC of developed with ease access has to streaming. been real-time media Thatwhy is 4. WebRTC Security andprivacy RFC 4960https://tools.ietf.org/html/rfc4960 plug-in -

22 It’s not magic, Interfaces and protocols for video calls published as an soon RFC. ofset and protocols by used WebRTC inan are Internet-Draft, described be whichwill tocol in signalingwidely WebRTC used applications). considerations Security related to the ers that support WebRTC.data P2P all transfers.secure Thisto is used ICE the During process, data using is DTLS encrypted that must integrated be into brows all - TCP and DTLS over UDP. Currently, DTLS at runs version 1.2,published in2012. communications. The main difference twothese between protocols that is runs TLS over nipulation. It on isTLS(Transport based protocol an extended Layer security Security), for This protocol provides incommunications privacy and prevents its interception and ma- 4.1. DTLS -Datagram conferencing,based 44 43 on web, the According to RFC7478regarding and cases use requirements inreal-time communications 4.3. Permissions inbrowser or web application multiple streams. content, RTCP captures stream statistics and and quality helps of to service, synchronize Protocol), allows which tracking and monitoring sending the of packets. While RTP streams WebRTC. RTP over runs UDP and in conjunction is used with RTCP (Real-Time Control dations of VoIP, hence it is implemented inmany other communication systems besides RTP was initially published in1996and updated in2003.It is one of foun technical the - RTPin the and RTCP protocols. in2004,SRTPvice. Released establishes an and encryption authentication system for traffic listenparties to or broadcasts, view and to risks of minimizethe attacks such of as denial ser Similarly to DTLS, WebRTC SRTP via media encrypts also to ensure that unauthorized third 4.2. SRTP -Secure Real–Time Transport Protocol denied. Furthermore, browsers should implement some mechanism to report camera when by users. This is implementedusually through a messagewhere accesscanbe accepted or mechanisms several vide to guarantee consent of access to camera, microphone and screen, 45 WebRTCSecurity Architecture. Privacy Enhanced RTP Conferencing (perc) https://datatracker.ietf.org/wg/perc/about/ Web Real-Time Communication Use Cases andRequirements. https://tools.ietf.org/html/rfc7478 45 the browser the that establishes acommunication through WebRTC should pro- 43 which works which the on specifically SRTP protocol, but also on SIP (a pro- 44 https://tools.ietf.org/html/draft-ietf-rtcweb-security-arch-20 RFC 3711https://tools.ietf.org/html/rfc3711 RFC 6347https://tools.ietf.org/html/rfc6347

-

23 It’s not magic, Interfaces and protocols for video calls encryption deploymentencryption multiparty inthese sessions, such as Jitsi,through intermediate services, calling Some video are servers. testing an E2E sessions), layer encryption the provided by DTLS and SRTP is removed packets when pass otherOn the hand, communications when are more between than two people (multiparty in RFC5763, onethe hand, inP2Pcommunications are E2Eusing DTLS encrypted and SRTP, as detailed implementationthe of DTLS and SRTP protocols security different be will eachcase. On in WebRTC for used can be communication two people between or larger between groups, and 4.4.About end-to-end encryption munication inorder them, between to receive and any send data flow. that implement WebRTC should ensure that users consent their establishment the of com- should able be toand review revoke permission this at any and, time for that, applications and microphone are what used, being is usually done through an icon. In addition, users 46 applications using real-time protocols: Following layer the structure, browsers should have functionalities for these execution the of 5. WebRTC inBrowsers Streams API. 49 48 47 management Connection controland Presentation local system Support to the Datagram Transport Layer Security(DTLS) https://tools.ietf.org/html/rfc5763 Framework for EstablishingaSecure Real-time Transport Protocol (SRTP) SecurityContext Using h Overview: Real Time Protocols for Browser-based Applications encryption-e2ee/ with-webrtc-insertable-streams/ andhttps://webrtchacks.com/you-dont-have-end-to-end- Avances para cifrado punto apunto enhttps://webrtchacks.com/true-end-to-end-encryption- WebRTC InsertableStreams https://www.chromestatus.com/feature/6321945865879552 This is what end-to-end encryption shouldlooklike! https://jitsi.org/blog/e2ee/ ttps://datatracker.ietf.org/doc/draft-ietf-rtcweb-overview/ 46 48 even if the packet evenifthe is sent through intermediaries, for example TURNservers. SDP, SIP, and Jingle /XMPP. formats during To acall. category this belong signaling protocols such as Establishment of connections, agreement on data formats, changes in data screen layout, voice activation of image switching, among others. standardized interfaces for functions. For these instance, ground control, ration of participants is required. Many applications have built been without guaranteeThey that interactions do notbehave in a surprising way,- coope rating system and ability to record locally. authenticationtion, local and authorization mechanisms, access to ope the - how to do it, without affectingtransmission.the For example:echo cancella - do They notbe uniformly each since to participantneed specified can choose 49 47 on basis of the WebRTC Insertable

24 It’s not magic, Interfaces and protocols for video calls lowing table. To provide more up-to-date data on browsers’ WebRTC support, we have prepared fol the - other Chrome-based browsers, without giving much more detail. lowing browsers: data from other projects such as caniuse.com Nonetheless, it an to seems be outdated and under-referenced information that contradicts clear andvery complete there, inEnglish. especially point, it is important to say that information technical the on real-time communications is fromnect operating certain systems and web browsers. According to Wikipedia, and at this browsers,between but we didnot find up-to-date documentation on how well canwe con- WebRTC promises interoperability and for ease establishing and video audio connections 52 51 50 WebRTC ternet byed , UC Browser andMini browsers. references Other on in - the com offers a more comparison detailed thatand reports specifically WebRTC is not support- Data transport Data framing Data formats Data Computers MicrosoftEdge 12+ 1.9+ 18+ Opera 11+ Mozilla Firefox 22+ ChromeGoogle 28+ 52 specify that WebRTC specify is compatible with Chrome, Mozilla Firefox, Safari, and Opera articles/216077528-Which-web-browsers-are-currently-supporting-WebRTC Which web browsers are currently supporting WebRTC? https://support.pexip.com/hc/en-us/ Supports WebRTC?Who WebRTC Peer-to-peer connections https://caniuse.com/#feat=rtcpeerconnection https://en.wikipedia.org/wiki/WebRTC#support gement of congestion, bandwidth and estimation. participantsbetween and functionalities to todata: when send decide mana- Protocols such as TCP, UDP, SCTPand means to establish safe connections guarantee data integrity and confidentiality. Protocols like RTP, SRTP, DTLS, as containers and others.serve They and for data that systems. between passes specifications Codec for audio andvideo, as well as format functionalityand https://www.3cx.com/webrtc/which-browsers-support-webrtc/; Android devices Android devices Google ChromeGoogle 28+ Opera MobileOpera 12+ Mozilla Firefox 24+ 51 and testsout the carried by ourselves. caniuse. 50 WebRTC is compatible with fol the - iOS devices MobileSafari/WebKit (iOS11+)

25 It’s not magic, Interfaces and protocols for video calls Windows 10 Debian 10 system (OS) Operating based iOS Android MacOS (usage rate*) Browser  No browser-OS compatibility  wpt test test call  bbb  Jitsi test call Leyend: 55 54 53 Web-platform-tests offers public test development for following indications the browserthe of your choice. There areseries of a tests for WebRTC UC Browser Opera Edge Chrome Firefox Browser (63,97%) Chrome      Test https://web-platform-tests.org/running-tests/from-local-system.html Running Tests from the Local System. Directory listing for /webrtc/ https://wpt.live/webrtc/ The : Browser technologies https://platform.html5.org/ Yes

Version 83 83 83 83 83 (16,96%) Safari   55    T and are intables collected 2and 3. No 6 69 83 83 78 Version Table 2.web-platform-tests on Windows 10    13 13 V Table 1.WebRTC support inbrowsers (4,44%) Firefox      T No 68 78 28 68 V

(3,39%) Internet Samsung      T Yes 87 1244 1270 1288 1058 Approved Tests     12 V (2,69 %) UC Browser      T No Red Yellow Green Color code:   13 13 13 V

(2,2%) Opera      T 54 , which we carry out we, which carry 53 Yes that in run can be Not working Working with errors Working Touch 2 Touch 2 17 313 314 304 706 Failed Test 69 69 69 V (2,11%) Edge      T Yes  45 45 83 83 V (1,79%) IE      T No 26     11 It’s not magic, Interfaces and protocols for video calls V The web is plenty of information on how WebRTC works. inEnglishAlmost all and aimed standing have that purpose. least to wonder about it. This document and our previous exercise and underof inquiry ences. However, to transform something to it understand is necessary how it works, or at Joining a conversationtechnical there if is difficult, especially are disagreements and differ 6. All this forwhat? this 6. All calls? make video affect this freedomdoes our and autonomywhen softwareas which users, choosing use to to How are large corporations influencingthe development of standards like WebRTC? How Hangouts, (Google vices Meets are Duo) on and Google WebRTC, based Google we wonder: today continues one to be of main the project promoters, and that its main ser calling video wasConsidering brand the that Google that promoted WebRTC as an open standard, what browsers on its (based offers, code) translated is into consumption. browsersbased better support WebRTC and how compatibility, Chrome which and other velopers are encountering to make compatible them with WebRTC, but why also Chrome- Given results, these it important seems to know more about what difficulties browser de- scored compatibility. their browsers mostthe used worldwide, Chrome while and browsers the on its based under code From data the obtained in our tests, we can conclude that WebRTC is not supported fully by 57 56 supported it, but there no open standard is still regard. inthis solutionscryption have implemented been inspecific applications someand browsers have essarily there must an be intermediate server, such as group Until calls. video now, some en- In May 2020,IETF resumed work streams E2Emedia in 2017 on started encrypt - nec when lowed on an open mailing list, Browser Firefox Chrome Chromium Opera https://www.ietf.org/mailman/listinfo/sframe Frame-based end-to-end encryption of real-time media media-encryption-with-webrtc-now-in-chrome/ https://webrtcbydralex.com/index.php/2020/03/30/secure-frames-sframes-end-to-end- Secure Frames (SFrames): end-to-end mediaencryption with #webrtc now inchrome. Version 68 83 83 69 Table 3.Web-platform-tests on Debian 10 57 where it to would have good be amore diverse participation. Approved Tests Error ejecutar al 1334 1221 1264

56 The conversationcanbe fol - Failed Test Error ejecutar al 332 310 307

- - - -

27 It’s not magic, Interfaces and protocols for video calls We leave questions these open. make its complexity more visible and legible? possibility.this Is it possible to communicate with less complex systems? Is it possible to The design complexof highly communication systems putsfurther andfurther away us from imagine other systems, where submission is not neither rule, nor the inuse indevelopment. onlence traditional based systems of oppression. Understanding how work they allows us to on made screens us the an also of object attacks. exposure the of calls, thanks to of video ouruse the tools, digital especially voices and bodies ifduring pandemicBecause the we were able to continue with our organizational processes hoping that it may of be interest and utility to our colleagues. information and explain it coherently for different us, users with very capacities, technical ment, with its failures and successes, is result the of an exercise that sought to gather this all at developers interested inimplementing or adapting standard the - to This needs. docu their 60 59 58 With or without apandemic, there are many strategies that we can work on Protected from whom, or from what? In hands whose are we allotting that protection? public? If how we call, make video sure asecure are we that our information is protected? implies claiming control over our information. If issues personal are it be political, also will tain affective relationships of different the in distance, types claiming necessarily privacy If tools the we to use work, organize and disseminate are ideas same the with we which main- and geographical location. evidently. Violence that, of course, is intensified due to conditions of race, class, abilities, age pandemic only made violence the to women which and gender diversities are more exposed https://acoso.online/cl/emergencia/ pornographic content inplatforms or anyother type of onlinegender-based violence Emergencia.Acoso.Online. Available materials to know what to doin case of nonconsensual america-latina/ https://www.derechosdigitales.org/14716/la-otra-pandemia-internet-y-violencia-de-genero-en- La otra pandemia:internet y violencia degénero en América Latina Trolls pandémicos https://www.pikaramagazine.com/2020/05/trolls-pandemicos/ 59 58 This, of course, is scenario.not a new The

60 to eradicate- vio

28 It’s not magic, Interfaces and protocols for video calls 29 It’s not magic, Interfaces and protocols for video calls