Intro WIP

chapter-introduction/chapter.tex

@@ -51,12 +51,62 @@ We conclude this thesis with an overview of two concrete use cases IHSMs unlock
 conventional HSMs: Datacenter-scale Secure Multiparty Computation (SMPC) and long-range Quantum Key Distribution (QKD)
 networks.
 
+\section{Building Inertial HSMs}
 
+In a system with a secure software stack, the role of a HSM is to secure the hardware part of the stack. The basic
+approach of a HSM is to combine a secure software stack with a fast self-destruct mechanism and tamper sensors. The
+self-destruct mechanism can be hardware or software that quickly, securely wipes all cryptographic secrets, rendering
+the device worthless to an attacker. The tamper sensors are tasked with detecting any physical attack an attacker could
+mount on the device. Common classes of such sensors include \emph{tamper-sensing meshes}, i.e.\ flexible foils attached
+to the HSM's enclosure that detect attempts at penetrating the shell of the device with probes, and environmental
+sensors such as temperature or radiation sensors that detect attempts at causing controllable faults in the HSM by
+heating, cooling or irradiating it. Out of these sensors, the tamper-sensing meshes are the core line of defense against
+most physical attacks. Such meshes are very effective at mitigating almost all physical attacks, but they are difficult
+to construct securely as they usually require bespoke manufacturing processes. As a result, they are currently only used
+in niche applications, and even there not every realization is equally secure.
 
-%In cryptography, Kerckhoffs' principle, named after Dutch military cryptographer Auguste Kerckhoffs, expresses that the
-%security of a cryptographic system should only depend on the secrecy of its keys, not on the secrecy of its design. In
-%this way, Kerckhoff's principle states the opposite of the common industry practice of \emph{Security by Obscurity},
-%which aims to achieve security by making it sufficiently annoying to cryptoanalyze a system that nobody bothers.
+Inertial HSMs solve the issue of creating an impenetrable tamper-sensing envelope by replacing the bespoke
+tamper-sensing mesh foil with a set of simple, rigid meshes made from commodity Printed Circuit Boards (PCBs) that are
+rotating at high speed. In motion, these simple PCB tamper-sensing meshes are as secure as the much more sophisticated
+bespoke foils used in conventional HSMs, yet they are simpler and less expensive to manufacture. To verify that the mesh
+is rotating correctly, an accelerometer is placed on the rotating mesh, and its centrifugal force reading is used to
+validate its path of motion.
+
+\section{Cryptographic Principles and Physical Reality}
+
+Cryptographers' aversion to backdoor access derives from a combination of two fundamental computing principles:
+Kerckhoffs' principle, and the principle of least authority. In cryptography, Kerckhoffs' principle, named after Dutch
+military cryptographer Auguste Kerckhoffs, expresses that the security of a cryptographic system should only depend on
+the secrecy of its keys, not on the secrecy of its design. In this way, Kerckhoff's principle states the opposite of the
+common industry practice of \emph{Security by Obscurity}, which aims to achieve security by making it sufficiently
+annoying to cryptoanalyze a system that nobody bothers. Complementary to Kerckhoff's is the principle of least
+authority, which describes that in a secure system each component should only have access to the smallest set of
+capabilities necessary to fulfill its purpose. Applying both to a cryptographic system means that the system's design
+should be transparent and not include any hiddent components or opaque parts that cannot be inspected, and that the
+system's keys should be scoped to place the least amount of trust possible in each participating party.
+
+Let's take a basic videoconferencing system as an example. In our example system's deployment, users logen to a central
+conference server, which receives and distributes the users' video streams. Allowing backdoor access to the video
+streams to some third party like a datacenter operator or a state would violate Kerckhoffs' principle since it would
+have to be hidden from the systems' participants, who would therefore not have a complete view of the systems' deployed
+architecture. The principle of least authority would also be violated since in almost all cases, such a backdoor access
+system would not see legitimate use. As a result, it would possess capabilities that almost never would be essential to
+the proper function of the videoconference system.
+
+In their design, almost all modern software -- especially open source -- cleanly applies these principles. However, the
+practical reality after deployment almost always deviates from them. While backdoors are vanishingly rare in modern
+open-source software, practical depoloyments usually are vulnerable to physical attacks. Modern hardware generally is
+not designed with a local attacker with advanced physical attack capabilities in mind since no mitigation can fully
+prevent them, they can only be detected, or at best slowed down. As a result, commonplace attacks against modern
+software often involve taking over the hardware at some point in the chain. Even End-to-End-Encrypted (E2EE)
+communication systems can be compromised if one of the encrypted channel's endpoints can be physically compromised.
+Corresponding \emph{digital forensics} capabilities are commonplace among state actors, and are available as a turnkey
+solution on the market.
+
+A consequence of the difficulty of defending against physical attacks along with the wide availability of attack tools
+and services is that
+
+\section{Inertial HSM Applications}
 
 
 %In the early days of mass-market computing, the expectations towards this new tool were high. Even before people
@@ -90,8 +140,6 @@ networks.
 
 
 % Cypherpunks
-
-\section{Centralized Authority}
 % ACAB is a anti-authoritarian sentiment
 % In anarchist discourse, "cops" are not just policemen and -women, but also other means of centralized control.
 % Anarchism rejects centralized authority in favor of the freedom of individuals because it recognizes the dangers