Post Quantum Cryptography Security in the Quantum Era: PQC for Embedded Systems

Quantum computing could put established encryption methods at risk. Infineon examines how secure elements and PQC-enabled microcontrollers can protect embedded systems against future threats—and why the transition requires more than new cryptographic algorithms.

As quantum computing advances, modern cybersecurity faces significant challenges: ongoing real-world attacks such as ransomware, phishing, and supply chain compromises, and a long-term structural threat posed by quantum computers. While today’s cryptographic systems are designed to protect against attacks using classical computers, future quantum capabilities require a fundamental reassessment of digital trust. Post-quantum cryptography (PQC) addresses this shift by enabling secured communication and authentication in a post-quantum world.

Quantum Computing and the Cryptographic Risk

Conventional computers process information in bits, either 1 or 0. Quantum computers use qubits, which, through superposition can represent both states at once, enabling new computing paradigms (Fig. 1). At the same time, cryptographically relevant quantum computers (CRQCs) could break widely used public-key algorithms such as RSA and ECC, undermining today’s digital trust infrastructure.

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Even before CRQCs exist, organizations face the risk of “harvest now, decrypt later” attacks, where encrypted data is stored today and decrypted once sufficient quantum capabilities become available. This threatens sensitive information and critical infrastructure, including financial systems, healthcare networks, and energy grids.

The Rise of Post-Quantum Cryptography

To address these risks, the cybersecurity industry is actively preparing for the transition to post-quantum cryptography. This refers to cryptographic algorithms that are resistant to both classical and quantum attacks and are intended to replace or supplement existing cryptographic systems without disrupting global communication infrastructure.

Standardization efforts led by the National Institute of Standards and Technology (NIST) provide an important basis for long-term PQC deployment. The most relevant standardized and selected algorithms include ML-KEM for key encapsulation, ML-DSA and FN-DSA for digital signatures, and SLH-DSA as a hash-based alternative.

In embedded systems, limited RAM, flash memory, CPU performance, and communication bandwidth strongly influence PQC algorithm selection. Compared to ECC, post-quantum algorithms typically require larger keys, signatures, and certificates, which increases memory, processing, and bandwidth demands. Migration to PQC is therefore a system-level engineering challenge that affects hardware selection, software architecture, and overall security design, not just a cryptographic update.

Security Architectures for PQC Systems

To address these challenges, dedicated hardware-based security architectures are becoming increasingly important for enabling efficient PQC deployment. Security controllers and PQC-enabled microcontrollers represent two complementary approaches for implementing PQC in embedded systems, each offering different advantages depending on application requirements.

Security controllers and Secure Elements

Secure Elements (SE) are dedicated security components designed for environments with severe constraints and high security requirements. They typically operate under strict limitations in terms of memory, communication bandwidth, and computational power, while providing strong protection against physical and side-channel attacks.

Infineon’s OPTIGA TPM is an embedded security solution that integrates post-quantum cryptography to help protect connected devices against future attacks by quantum computers, including firmware updates and root-of-trust authentication.

Such devices are widely used in applications ranging from industrial IoT and consumer devices to payment systems, identification solutions, and automotive Digital Key and secured vehicle access systems. This is particularly relevant for automotive applications such as Car Access and Digital Key ecosystems, where digital credentials can be provisioned, shared, and managed across multiple users and devices. Strong authentication and protected key storage are essential to allow access rights to be granted, transferred, and revoked while preventing unauthorized access.

Infineon’s TEGRION SLC27 security controller family provides a security foundation for various Secure Element and security controller solutions, enabling robust protection of cryptographic assets and reliable execution of sensitive operations.

Not all PQC schemes are equally suitable for Secure Element environments, where implementation efficiency and resource use are critical. ML-KEM is well suited for key encapsulation, ML-DSA for digital signatures, XMSS and LMS for secure boot verification, and FN-DSA for use cases where compact signature size is important.

PQC for Microcontrollers

While Secure Elements provide dedicated hardware-based security functions as separate components, PQC-enabled security functions can also be integrated directly into the microcontroller architecture. Examples include microcontrollers such as Infineon’s PSOC Control C3 (Fig. 2) and PSOC Edge families (Fig. 3), as well as Infineon’s automotive PQC-enabled microcontrollers, TRAVEO T2G (Fig. 4) and AURIX TC4x family (Fig. 5), which implement a hardware-based Root of Trust, Secure Boot mechanisms, Arm® TrustZone-M-based isolation, and dedicated cryptographic accelerators.

Dedicated acceleration for hash- and lattice-based algorithms improves PQC performance and makes these MCUs suitable for embedded systems that require both speed and cryptographic flexibility.

Combining Both Approaches

PQC-enabled microcontrollers and Secure Elements serve complementary roles: microcontrollers provide high performance, flexibility, and integrated cryptographic acceleration, while Secure Elements enable secured key storage and isolate critical operations in physically hardened environments. A hybrid architecture combines these strengths and supports cryptographic agility, enabling systems to adapt to evolving PQC standards through updatable software on suitable hardware platforms.

Conclusion

Post-quantum cryptography represents a necessary advancement to address the rise of quantum computing. While current systems remain sufficiently protected against classical attacks, CRQCs could fundamentally undermine existing public-key infrastructures. The successful implementation of PQC therefore requires not only quantum-resistant algorithms but also hardware architectures that meet the increased demands for performance, memory, and flexibility. Secure Elements and PQC-enabled MCU architectures will form the foundation of future quantum-resistant embedded systems. (sb)

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