Protect your data

With the information on this website, you will learn how to protect your source and how to choose the proper level of protection that suits your needs, depending on the thread model.

The content of this book is largely derived from the book 'Infosec for investigative journalists’, written by Silkie Carlo and Arjen Kamphuis in 2014. In December 2016 I provided for the Dutch translation of the book. Since 2018 it has been updated every year. The Dutch version was handed to the NVJ (Dutch association of journalists) in February 2017. It has been used by the newspaper NRC to train their journalists. The latest update of the English original dates back to 2016 (by Silkie Carlo). In January 2020 I updated it to get it in line with the Dutch publication. The 2018 update is based on the book 'Personal Information Security', which I co-authored with Arjen Kamphuis for the Dutch association, 'Broodfonds'.


Logan Handbook
Logan Handbook

In the original book, Silkie Carlo thanks cybersecurity expert Arjen Kamphuis for his patience, generous teaching and his patience and Gavin MacFayden/CIJ for the assignment. Arjen thanks his parents and the Free Software Foundation On my turn I thank Arjen for his explanations and everything he taught me.

In late August 2018, Arjen went missing in Norway and it was never clear what exactly happened. A sad situation. Police assume he drowned after a kayaking accident. In 2022, Sanne Terlingen and I conducted a very extensive investigation in consultation with the family, the co-owner of Arjen's company Gendo and the Norwegian police. Through a crowdfunding campaign, money was additionally raised so that forensic pathologist Frank van der Goot could conduct on-site investigations. In the end, we independently came to the conclusion that the most likely scenario is that Arjen had an accident while kayaking, albeit at a different place and time than the police assumed. However, his body has not been found.

I know he expected or hoped I would keep updating the book. And as long is this is useful, I will, not just because I respect his work and his tireless energy to help people with digital self-defense but also because the topic is increasingly important.

Helma de Boer – Zwolle, 2020

Free download

This handbook is in the tradition of Silkie and Arjen, offered as a free download. If you appreciate this work, consider to donate to the Centre for Investigative Journalism (CIJ, UK), the Dutch 'Nederlandse Vereniging voor Journalisten' (NVJ) or the Dutch 'Vereniging van Onderzoekjournalisten (VVOJ).

Here you will find the 2020 English edition of this book by Silkie Carlo (May 2016). An update to the 2020 version by me, you wil find here: