ARM Security Technology Building a Secure System using ...

Introduction
1.2 The need for security
1.2.1 Hardware enforced security
Embedded devices are handling data of increasing value, such as consumer banking
credentials. They are also steadily becoming open software platforms with high levels
of off-device connectivity that enable the consumer to download arbitrary third-party
applications. This puts these devices in a high risk position. In the desktop environment
the combination of open software platforms, arbitrary application download, and
valuable assets present on the device, have been shown to significantly increase the risk
of a security vulnerability being exploited. Additionally, if the value of data passing
through these systems is increasing, it is more likely that attackers will invest in
breaking them.
Malicious Download
Exploitable Flaw
System Call Interface
Banking Application
Passcode
Operating System Kernel
Figure 1-1 : Attacking an application
The aim of the ARM TrustZone technology is to enable a device to benefit from both a
feature-rich open operating environment and a robust security solution. A well designed
system hardware architecture and appropriate secure software design can ensure that the
sensitive data remains safe, no matter what the less trusted operating environment does.
Making an embedded product safe from malicious attacks has consequences for the
entire system design. The hardware and software present in the device must work
together to enable robust security countermeasures against the correct types of attack.
The Trusted Computing Group whitepaper “Securing Mobile Devices on Converged
Networks” identifies that the best protected systems have dedicated hardware security
measures included from the beginning of their design process, starting with the
specification for the processor core and the SoC infrastructure. Careful consideration of
hardware security at this early stage allows protection to be built into the device that
would be impossible to add later in the design process.
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