Looking Back: Hacking and Defending Windows Public Key Infrastructure (ADCS)

I live at the fringes of the cybersecurity community. I have never attended infosec conferences. There will be a talk on PKI hacking at Blackhat 2021 soon: Top AD offensive security gurus are presenting comprehensive research on abusing ADCS (Active Directory Certificate Services). I only know about that, because I noticed backlinks from their article … Continue reading Looking Back: Hacking and Defending Windows Public Key Infrastructure (ADCS)

Reality and Imagination

Grey and colorful. Cutting through each other. Chasing each other. Meeting in the center, leaning on each other, forming an infinite line. ~ Reality and Imagination: Real and imaginary part of complex function 1/z: ~ The real part of 1/z is painted in shades of grey, the imaginary part in rainbow colors. Plots are created … Continue reading Reality and Imagination

Vintage Covectors

Covectors in the Dual Space. This sounds like an alien tribe living in a parallel universe hitherto unknown to humans. In this lectures on General Relativity, Prof. Frederic Schuller says: Now comes a much-feared topic: Dual vector space. And it's totally unclear why this is such a feared topic! A vector feels familiar: three numbers … Continue reading Vintage Covectors

Injecting an EFS Recovery Agent – and Let the Virus Scanner Help You!

How can you read files encrypted with Windows's Encrypting File System if you neither have access to the owner's encryption certificate and key and nor that of a legit data recovery agent (DRA) ... but if you are a local administrator? This work is still inspired by the hackthebox machine Helpline. You were able to … Continue reading Injecting an EFS Recovery Agent – and Let the Virus Scanner Help You!

Peter M. Schuster on History of Science

The late Dr. Peter M. Schuster was a physicist and historian of science. After a career in industry, he founded a laser technology startup. Recovering from severe illness, he sold his company and became an author, science writer, and historian. He founded echophysics - the European Center for the History of Physics - in Pöllau … Continue reading Peter M. Schuster on History of Science

Dirac’s Belt Trick

Is classical physics boring? In his preface to Volume 1 of The Feynman Lectures on Physics, Richard Feynman worries about students' enthusiasm: ... They have heard a lot about how interesting and exciting physics is—the theory of relativity, quantum mechanics, and other modern ideas. By the end of two years of our previous course, many … Continue reading Dirac’s Belt Trick

Motivational Function


Deadly mutants are after us. What can give us hope? This innocuous-looking function is a sublime light in the dark. It proves you can always recover. If your perseverance is infinite. $latex e^{\left(-\frac{1}{x^{2}}\right)}&s=3 $ As x tends to zero, the exponent tends to minus infinity. The function's value at zero tends to zero. It is … Continue reading Motivational Function


New Year's Eve 2019 seems infinitely far in the past. It was the first day news about this mysterious disease had been published in my country. Yet it seems infinitely far away at that time, somewhere in China. Today we see something glowing at the end of a weird long corridor. Despite horrible news, I … Continue reading Infinity

Gödel’s Proof

Gödel's proof is the (meta-)mathematical counterpart of the paradoxical statement This sentence is false. In his epic 1979 debut book Gödel, Escher, Bach Douglas Hofstadter intertwines computer science, math, art, biology with a simplified version of the proof. In 2007 he revisits these ideas in I Am a Strange Loop. Hofstadter writes: ... at age … Continue reading Gödel’s Proof


When you move from fundamental principles (in physics)  to calculating something 'useful' (in engineering), you seem to move from energy to enthalpy. Enthalpy is measured in Joule, as well as energy. It is assigned to a 'system', a part of the physical world separated from other parts by interfaces. The canonical example is a vessel … Continue reading Enthalpy