Andreas Renz

Andreas Renz is a cryptologist & cybersecurity researcher based in Switzerland. He writes fiction about systems that shouldn't break, and the people who break them. He works on the problems that appear when cryptographic assumptions meet deployed reality: post-quantum migration for organizations that do not want to migrate, protocol analysis in the gaps between published standards, and the operational consequences of key rotation decisions made a decade before anyone had practical reason to care. His day-to-day work sits in applied cryptography and cybersecurity — the kind of problems that only matter once a standard is being deployed. Which is probably why the fiction reads the way it does.

Cleartext is his debut novel. It is a near-future thriller about the months after the math that protects the internet quietly stops working. The book follows two people on opposite ends of the same machine. Marcus Wynthor is a twenty-nine-year-old security engineer in Austin who finds an API endpoint he should not have access to. Kai Merrowe is the senior NSA cryptanalyst who helped architect what is on the other end of it. The technology in the book is drawn from current post-quantum research, primary-source documents on US signals intelligence, and the institutional machinery that makes both of those things continue to function without most of the people inside them knowing how.

He writes non-fiction at encryptorium.com under the handle 0xLoopTheory, where the topics tend to be whichever part of the post-quantum migration problem is most visibly broken that month. The audience for that work is practitioners: engineers running real systems, compliance teams arguing with auditors, security researchers who want the detail without the marketing layer.

The fiction comes from the same material, turned ninety degrees. Cleartext started as an essay on harvest-now-decrypt-later and the way institutional incentives discourage pressing on the uncomfortable questions. The essay did not finish. What kept coming back, underneath the argument, were two people he could see clearly: the engineer who cannot stop pulling on a thread, and the analyst who cannot unsee what his own work is being used to do. The essay became a book.

The writing rules he keeps are narrow. No invented cryptography. No invented agencies. Where the book describes a program, a protocol, or a limitation, the constraint behind it is real. Where it invents a name, the shape of the thing the name refers to matches a real institutional pattern. Readers should be able to put the book down, look up anything technical that bothered them, and come back with the broader picture intact.

He reads too many IACR preprints for someone writing fiction, and answers email. For cryptography inquiries: encryptorium.com. For the book, press, podcasts, and readers: the contact links on this site.