In my 2008 novel Little Brother, the underground resistance uses a secure operating system called "Paranoid Linux" that is designed to prevent surveillance and leave no evidence of its use; that was fiction, but there's a real Paranoid Linux out there: Tails, The Amnesic Incognito Live System, and it turns 10 today.
Tails is a fork of Debian, a popular GNU/Linux operating system, stripped down and re-engineered so that you can boot most PCs from a Tails thumbdrive, use the web securely and anonymously, and shut the system down again without leaving any trace behind.
Edward Snowden used Tails when he was communicating with the journalists to whom he passed his trove of documents; I used Tails when I was researching, reporting and publishing one of those documents.
Today, Snowden continues to endorse Tails: "If I were going to reprise my work in 2013 in a 2019 environment, I'd almost certainly still use Tor and Tails."
The volunteers who maintain Tails (read their "social contract") have updated it 98 times since its launch, and served 25,000,000 copies to the public for free. They have ambitious plans for the coming year: simplifying docs to make them accessible to nonexpert users, improving the UI and design, creating new training docs in four languages, and adding Secureboot support.
In 2018 and 2019:
* 66 different people contributed to our main source code, including coders, writers, and translators.
* 22 different people were paid to work on Tails: a few of them full-time, most of them part-time or as consultants.
* We attended 21 conferences in 10 different countries to stay connected with the communities of the Tails ecosystem: related Free Software projects, digital security trainers, and users.
* 20 people, both workers and volunteers, attended our yearly gatherings.
Meanwhile, we counted no less than 21 projects, who also tried to build a live operating system for privacy and anonymity but are now abandoned.
A big thank you to everybody who either contributed to Tails or supported us:
Celebrating 10 years of Tails! [Tails]