Electronics Guide

Security and Cryptography

Security has become a fundamental requirement for embedded systems as they increasingly connect to networks, handle sensitive data, and control critical infrastructure. From protecting intellectual property in consumer devices to securing industrial control systems against cyberattacks, embedded security encompasses hardware protection mechanisms, cryptographic implementations, secure software development, and comprehensive threat mitigation strategies.

Unlike general-purpose computing platforms with abundant resources, embedded systems must implement security within strict constraints of processing power, memory, energy consumption, and cost. This category explores the specialized techniques, architectures, and best practices that enable engineers to build secure embedded systems that protect against both physical and remote attacks while meeting demanding operational requirements.

Articles

Core Security Concepts

Embedded security is built upon fundamental principles that guide system design and implementation:

Defense in depth: No single security mechanism is sufficient. Effective security layers multiple protections so that compromise of one mechanism does not grant complete access. Hardware security foundations, secure boot processes, encrypted communications, and runtime protections work together to create comprehensive security.

Least privilege: Each component should have only the minimum access and capabilities required for its function. Privilege separation limits the damage when any single component is compromised, containing breaches rather than allowing full system takeover.

Secure by design: Security must be considered from the earliest design stages, not added as an afterthought. Hardware security features, secure boot architecture, and protected interfaces are difficult or impossible to retrofit once systems are designed and deployed.

Trust boundaries: Clearly defined boundaries separate trusted from untrusted components. All data crossing trust boundaries must be validated, and communication between domains must be authenticated and protected.

Hardware Security Foundations

Hardware provides the root of trust upon which all other security measures depend:

Trusted execution environments: Hardware-isolated regions provide secure execution areas protected from the main processor and operating system. Technologies such as ARM TrustZone, Intel SGX, and dedicated security processors create protected enclaves for sensitive operations.

Hardware security modules: Dedicated security co-processors handle cryptographic operations, key storage, and secure element functions. These modules protect keys from extraction even when the main system is compromised.

Physical unclonable functions: PUFs generate device-unique cryptographic keys from inherent manufacturing variations. These keys cannot be extracted or cloned, providing strong device authentication and secure key generation.

Tamper detection and response: Physical security mechanisms detect intrusion attempts and respond by erasing keys or disabling functionality. Mesh sensors, environmental monitors, and active shields protect against physical attacks.

Cryptographic Implementation

Cryptography provides the mathematical foundation for security, but embedded implementation presents unique challenges:

Symmetric encryption: Algorithms such as AES provide efficient bulk data encryption. Hardware accelerators enable high-throughput encryption within power constraints. Mode selection and initialization vector management are critical for security.

Asymmetric cryptography: Public key algorithms enable key exchange, digital signatures, and authentication. Elliptic curve cryptography provides strong security with smaller key sizes suitable for constrained devices.

Hash functions and MACs: Cryptographic hash functions verify data integrity. Message authentication codes combine hashing with secret keys for authenticated integrity verification.

Side-channel resistance: Embedded cryptographic implementations must resist power analysis, timing attacks, and electromagnetic emanation analysis. Constant-time algorithms, masking techniques, and hardware countermeasures protect against these attacks.

Secure Development Practices

Security depends not only on cryptographic algorithms but on their correct implementation and integration:

Secure coding standards: Guidelines such as CERT C and MISRA address vulnerabilities common in embedded software. Buffer overflow prevention, input validation, and proper error handling eliminate entire classes of vulnerabilities.

Static and dynamic analysis: Automated tools identify potential vulnerabilities before deployment. Static analyzers find code patterns associated with security issues. Dynamic analysis and fuzzing discover runtime vulnerabilities.

Security testing: Penetration testing, vulnerability assessment, and security audits verify that implemented security meets requirements. Testing should cover both logical attacks and physical attack vectors.

Secure update mechanisms: Firmware update systems must authenticate updates, protect against rollback attacks, and maintain system availability. Over-the-air update security is critical for deployed devices.

About This Category

The articles in this category address the specialized knowledge required for securing embedded systems. Topics span hardware security mechanisms, cryptographic implementation, secure boot and attestation, and protection against both remote and physical attacks. Understanding these principles is essential for engineers developing systems that must protect sensitive data, intellectual property, or safety-critical functions in an increasingly hostile threat environment.