
Amjad Ouled-Ameur contributed to the zephyrproject-rtos/trusted-firmware-m repository by enhancing the robustness and security of CC3XX cryptographic components over a two-month period. He focused on low-level C and Assembly programming to address unaligned memory access, endianness, and stack zeroization in cryptographic drivers, improving both reliability and security. Amjad expanded test coverage for DRBG and PKA modules, integrating build flags for targeted test execution and automating validation across hardware platforms. His work included AES key loader integration, privileged memory configuration, and side-channel mitigation, demonstrating depth in embedded systems, cryptographic algorithms, and secure firmware development for trusted hardware environments.

In March 2025, delivered significant CC3XX-focused work in zephyrproject-rtos/trusted-firmware-m, improving cryptographic robustness, test automation, and security posture. Key features delivered and changes: - CC3XX DRBG core enhancements and fixes: AES external key loader integration; endian-safe DRBG CTR/HASH increments; addressed boundary and endianness issues. - CC3XX DRBG test coverage and infra: expanded DRBG tests (CTR, HASH, HMAC); added build flags to selectively enable tests; improved safeguards for DRBG test execution. - CC3XX security hardening and initialization: privileged AHB access configuration; relocation of SRAM encryption key setup to BL1_1; RNG robustness checks; cleanup and dead-code fixes to harden the stack against side-channel and fault risks. - CC3XX PKA tests: added tests for signed negative operands to validate handling of edge-case operands. Impact and business value: - Stronger cryptographic primitives with safer initialization and operation paths reduce risk of security vulnerabilities in trusted firmware. - More reliable, scalable testing with targeted build flags shortens CI cycles and accelerates validation of changes. - Improved hardware security posture (RNG robustness, side-channel mitigations) and clearer, auditable initialization flows support compliance and long-term maintainability. Technologies/skills demonstrated: - Embedded C, cryptographic primitives (CTR/HASH/HMAC, DRBG) and endianness handling; AES external key loader integration. - Test automation and CI optimization via build-flag-driven test suites; robust test infrastructure for cryptographic components. - Security hardening practices across BL1/BL1_1 layers, PKA integration, RNG checks, and DPA mitigation pathways.
In March 2025, delivered significant CC3XX-focused work in zephyrproject-rtos/trusted-firmware-m, improving cryptographic robustness, test automation, and security posture. Key features delivered and changes: - CC3XX DRBG core enhancements and fixes: AES external key loader integration; endian-safe DRBG CTR/HASH increments; addressed boundary and endianness issues. - CC3XX DRBG test coverage and infra: expanded DRBG tests (CTR, HASH, HMAC); added build flags to selectively enable tests; improved safeguards for DRBG test execution. - CC3XX security hardening and initialization: privileged AHB access configuration; relocation of SRAM encryption key setup to BL1_1; RNG robustness checks; cleanup and dead-code fixes to harden the stack against side-channel and fault risks. - CC3XX PKA tests: added tests for signed negative operands to validate handling of edge-case operands. Impact and business value: - Stronger cryptographic primitives with safer initialization and operation paths reduce risk of security vulnerabilities in trusted firmware. - More reliable, scalable testing with targeted build flags shortens CI cycles and accelerates validation of changes. - Improved hardware security posture (RNG robustness, side-channel mitigations) and clearer, auditable initialization flows support compliance and long-term maintainability. Technologies/skills demonstrated: - Embedded C, cryptographic primitives (CTR/HASH/HMAC, DRBG) and endianness handling; AES external key loader integration. - Test automation and CI optimization via build-flag-driven test suites; robust test infrastructure for cryptographic components. - Security hardening practices across BL1/BL1_1 layers, PKA integration, RNG checks, and DPA mitigation pathways.
February 2025 monthly summary for zephyrproject-rtos/trusted-firmware-m. Delivered security-focused robustness improvements to CC3XX cryptographic components and expanded low-level hardware abstraction support, with an emphasis on reliability, portability, and test coverage. Key changes include DRBG HASH hardening to correctly handle unaligned bytes, streamline HMAC lifecycle for long keys, and ensure alignment-safe memory access, alongside post-reseed entropy zeroization to prevent leakage. Also extended the PKA driver to support unaligned buffers for read/write operations and added tests to verify behavior on Little and Big Endian platforms.
February 2025 monthly summary for zephyrproject-rtos/trusted-firmware-m. Delivered security-focused robustness improvements to CC3XX cryptographic components and expanded low-level hardware abstraction support, with an emphasis on reliability, portability, and test coverage. Key changes include DRBG HASH hardening to correctly handle unaligned bytes, streamline HMAC lifecycle for long keys, and ensure alignment-safe memory access, alongside post-reseed entropy zeroization to prevent leakage. Also extended the PKA driver to support unaligned buffers for read/write operations and added tests to verify behavior on Little and Big Endian platforms.
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