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To secure digital
assets, a tasteful integration of a variety of technologies and processes is necessary.
Tamper-resistance is being increasingly used as an important piece of a more comprehensive
security system. It provides an effective barrier to entry and protects digital
assets in the embedded systems from most people and most attacks. Embedded systems
pose unique security challenges because they are largely used in relationships
where one party wants to put a secure, embedded device, in the hands of another,
with the assurance that the second party cannot modify/hack the device. First,
we outline the major attacks that threaten the security of an embedded system.
The vulnerability landscape of
an embedded system is a vast expanse of attacks. A good understanding of the threats
is necessary so that countermeasures can be devised to protect against threats
that pose the greatest risk. Second, we present countermeasures and discuss their
effectiveness in protecting the crown jewels of an embedded system: boot code,
operating system software and embedded hardware. A clear understanding of attacks
and countermeasures enables a system architect to make rational investment decisions
in designing a secure, embedded system.
Tamper-resistant
storage techniques provide varying degrees of authenticity and integrity for data.
This paper surveys five implemented tamper-resistant storage systems that use
encryption, cryptographic hashes, digital signatures and error-correction primitives
to provide varying levels of data protection. Five key evaluation points for such
systems are: (1) authenticity guarantees, (2) integrity guarantees, (3) confidentiality
guarantees, (4) performance overhead attributed to security, and (5) scalability
concerns. Immutable storage techniques can enhance tamper-resistant techniques.
Digital watermarking is not appropriate for tamper-resistance implemented in the
storage system rather than at the application level. '
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