When finishing a book, the time of acknowledgments is a pleasure and, to some extent, a surprise. It is at this moment that authors realise to what extent ‘their own’ work is actually the product of a collective endeavour – formal and informal interactions, moments of feedback and challenge, asking for help and taking stock, thanking and being grateful. To all the individuals and organisations listed below – and those we may have omitted by mistake – we are, indeed, deeply indebted for making this book what it is.

First of all, a heartfelt thank you to Mattering Press for taking this book project on board at the end of 2018, in a time-sensitive situation, and for following it carefully and benevolently ever since. Mattering is a wonderful experiment in researcher-led-and-owned, open publishing that we feel honoured to be a part of. Francesca had been hoping that a book project suitable for submission to MP would come along since she shared the ‘keynote spotlight’ with Julien McHardy at the 2014 meeting of the Spanish STS network (redCTS), and first heard about the promising nascent Press. She could not be happier that, seven years later, this ‘declaration of intentions’ which she made in a corner of her mind has come to fruition.

At Mattering Press, we wish to especially thank Joe Deville for the countless, kind and patient hours of work on both the content and form of our book – despite the multiple disruptions in personal and professional lives that the Covid-19 pandemic has caused since early 2020. Thank you so much, Joe.

We wish to thank the team of the H2020 NEXTLEAP project: Jaya Klara Brekke, George Danezis, Giacomo Gilmozzi, Marios Isaakides, Nadim Kobeissi, Wouter Lueks, Vincent Puig, Carmela Troncoso and all the other colleagues who joined the team for shorter periods of time but whose contributions to the project were crucial for its success. A special thanks to NEXTLEAP coordinator Harry Halpin, who first suggested back in 2014 that we should embark on a project on decentralised architectures together and has been a stimulating colleague and co-author throughout the project. A very special thanks to Holger Krekel, head of Merlinux GmbH and lead developer of Delta Chat; we are grateful for numerous insightful and kind conversations during the project, and beyond, on the informatics and philosophy of federation, and for his support of our work. We remember fondly Bernard Stiegler, who prematurely left us on 5 August 2020. His insights permeate the project and its practical and academic outputs.

We also wish to thank the European Commission for funding the NEXTLEAP project via its innovative programme ‘Collective Awareness Platforms for Sustainability and Social Innovation’ (CAPS). Year after year, CAPS-funded projects have produced very stimulating work on sustainability and citizenship in the digital age, and we hope that this book is another ‘brick in the wall’ in this regard. Thank you to Fabrizio Sestini and Loretta Anania, EC Project Officers at DG CONNECT, for their attentive and kind spearheading of the project. We are also grateful to Francesca Bria, Maurizio De Cecco and Stefania Milan, who kindly reviewed our work at different stages.

Our heartfelt thanks also go to Laura DeNardis, who graciously agreed to dedicate some time from her extremely busy schedule as Dean of American University’s School of Communication – and as one of the world’s foremost Internet governance scholars – to write the preface for the book. Her words mean so much to us, as they position our book as a valuable contribution to the academic enterprise that analyses technical infrastructures and architectures as arrangements of power, and they stress the importance of encryption as a core Internet governance controversy of our times.

As this book was developing, a project of a different kind saw the light – the Centre for Internet and Society of CNRS, which Francesca co-founded, and which has been the ‘professional home’ for us both since January 2019. Thank you to the colleagues who started the adventure of this new research unit with us, this book would not be the same without our ongoing interactions and conversations: CIS co-founder and director Mélanie Dulong de Rosnay, Olivier Alexandre, Maria Castaldo, Jean-Marc Galan, Axel Meunier, Tommaso Venturini and Céline Vaslin. We also wish to acknowledge the interactions with colleagues of the Groupement de recherche Internet, IA et Société, that constitutes a vital dimension of CIS. Let us mention here, in particular, colleagues and friends Séverine Arsène, Anne Bellon, Romain Badouard, Lucien Castex, Marida Di Crosta, Clément Mabi, Cécile Méadel, Julien Rossi, Félix Tréguer, Valérie Schafer and Guillaume Sire. We are also indebted to our former research unit, the Institute for Communication Sciences (ISCC) of CNRS, and its director, Pascal Griset, who for three years provided a comfortable and stimulating working environment for the NEXTLEAP project.

Our ability to continue our work on the NEXTLEAP-born investigation on encrypted secure messaging, and on its outputs including this book, was greatly boosted by obtaining funding for a closely related project, ResisTIC – The Net Resistants: Critique and Circumvention of Digital Coercion in Russia. Our thanks go to the French national funding body, the Agence Nationale de la Recherche (that also previously funded Francesca’s first substantial research project on decentralised architectures, ADAM, a predecessor to NEXTLEAP). We are also grateful to the ResisTIC team: Olga Bronnikova, Françoise Daucé, Fabrice Demarthon, Valéry Kossov, Benjamin Loveluck, Bella Ostromooukhova, Perrine Poupin and Anna Zaytseva, for the fruitful scientific exchanges and friendly conversations in the frame of the project and its seminars.

Over the years, a number of colleagues worldwide, beyond those already cited above, gave feedback on either the book proposal, on papers that eventually formed the basis of chapters or on draft chapters. Thank you, Sylvain Besençon, Nathalie Casemajor, Andrew Clement, Philip Di Salvo, Maxigas, Liudmila Sivetc, Sophie Toupin. Special acknowledgements go to Angela Sasse and Ruba Abu-Salma from UCL, who initiated us into usable security and kindly agreed to discuss our work at a very early stage.

During the writing of the book, Ksenia spent a year and a half at the Citizen Lab (University of Toronto, Canada) as a postdoctoral researcher, and wishes to thank its director Ronald Deibert as well as Masashi Crete-Nishihata, Jakob Dalek, John Scott-Railton, Bahr Abdul Razzak, Miles Kenyon, Lotus Ruan, Adam Senft and all the team. We both wish to acknowledge the Centre for the Sociology of Innovation of MINES ParisTech, where we conducted our PhD theses in a wonderfully stimulating environment and Francesca still holds an associate researcher appointment. Francesca also wishes to thank the editorial team of the Internet Policy Review, as well as the Internet Governance Lab of American University, to which she owes a fruitful collaboration with Laura DeNardis, Derrick Cogburn and Nanette Levinson.

More broadly, our work was enriched by a number of academic communities of which we are members. Our thanks go to the International Conferences on Internet Science (INSCI), the Society for the Social Studies of Science (4S) and the European Association for the Study of Science and Technology (EASST), the Association of Internet Researchers (AoIR), the Global Internet Governance Academic Network (GigaNet), The Center for Science and Technology Studies of the European University at Saint-Petersburg, and last but not least, the International Association for Media and Communication Research (IAMCR). Within IAMCR, we wish to acknowledge our joint work with Aphra Kerr, Julia Pohle, Jeremy Shtern and Weiyu Zhang, who co-chair(ed) with Francesca the Communication Policy and Technology Section, and Sylvia Blake, Sibo Chen and Steph Hill, who co-chair(ed) with Ksenia the Emerging Scholars Network.

We write about technical issues that are deeply political, and we hope that our work can be useful to policy. In this regard, being able to interact closely with institutions and NGOs is invaluable. Francesca wishes to thank the French Parliament’s Commission for Rights and Liberties in the Digital Age, the CSAlab and the Internet Society France for having engaged with the project and for involving her in their multi-stakeholder reflections on how to make the Internet more open, transparent and usable.

Last but not least, we wish to thank all the activist tech communities that have trusted us, assented to talk to us and assisted in arranging interviews with the most marginalised, at-risk user groups. A very special thanks goes to the Digital Security Lab Ukraine (namely Mykola Kostynyan, Vadym Hudyma, Iryna Chulivska, Maksim Lunochkin and others), Syster Servers collective, Campi Aperti project, Autistici, Riseup, Tails and Espiv. Very warm thanks to dkg, Samba, Vassilis and Spider Alex.

We could not finish these acknowledgments before thanking with all our hearts our families, for their love and support through thick and thin (as the first year of the Covid-19 pandemic concludes, this sentence stands for a whole lot of nuances). Chiara, Jean-Marc, Brune, Loïse, Marco, Patrizia, Carlo, Elena, Oksana, Sasha, Svetlana, Lerie and Timofey: this book is for you.