lowRISC/opentitan
Apr 2025 – Apr 2026
13 Months active
Languages Used
CJSONRustPythonStarlarkAssemblyMarkdownSystemVerilog
Technical Skills
C programmingembedded systemsfirmware developmentAssembly LanguageEmbedded SystemsFirmware Development
Siemen Dhooghe
PROFILE
Siemen Dhooghe
Siemen Dhooghe developed and maintained security-critical firmware and testing infrastructure for the lowRISC/opentitan repository, focusing on cryptographic robustness and penetration testing. He engineered modular test frameworks and enhanced secure boot validation, integrating C and Python to automate and harden test coverage across hardware and firmware. His work included implementing buffer integrity checks, hardened arithmetic, and fault-injection resistance, as well as optimizing build systems with Bazel. By addressing vulnerabilities such as padding or overflow risks and improving debugger reliability, Siemen ensured scalable, reliable validation workflows. His contributions demonstrated deep expertise in embedded systems, cryptography, and secure software engineering practices.
Overall Statistics
Feature vs Bugs
79%Features
Repository Contributions
141Total
Bugs
16
Commits
141
Features
59
Lines of code
78,673
Activity Months13
Your Network
4491 peopleSame Organization
@google.com4397
Benedict OdaiMember
Craig IngramMember
KayyuriMember
Scott SuarezMember
Agent2Agent (A2A) BotMember
Andreas AbelMember
Aadi KapurMember
Aadish GoelMember
Aahil MehtaMember
Work History
April 2026
6 Commits • 3 Features
Apr 1, 2026April 2026 monthly summary for lowRISC/opentitan: Implemented security hardening and release controls across the crypto stack, with targeted fixes to prevent padding or overflow vulnerabilities. Notable commits include hardened arithmetic with reversibility tests (b32efe5d923e1947ebfc0e73020b4e091454faa3, e81fe08706c2e081b14fc71f8437893596355819), release flag for cryptolib (47fac86058f60ab78dfa277c4c433692f2da1c84), AES-KWP exp_pad size standardization and DRBG buffer sizing (4cb47230d01ac2dff589b22a85de6e623cc2aafc, 75f7d2fe44f2e3da01511f8d4f0a4c6e0cbbdd64), and AES-GCM tag length check (ee4aad73d4a193892cb6f8baa2354ec333dacaea). Impact: strengthened resistance to fault injections, safer release builds, and improved reliability and performance in critical crypto paths. Value: reduces deployment risk and reinforces cryptographic guarantees in OT repositories.
6 Commits • 3 Features
Apr 1, 2026April 2026 monthly summary for lowRISC/opentitan: Implemented security hardening and release controls across the crypto stack, with targeted fixes to prevent padding or overflow vulnerabilities. Notable commits include hardened arithmetic with reversibility tests (b32efe5d923e1947ebfc0e73020b4e091454faa3, e81fe08706c2e081b14fc71f8437893596355819), release flag for cryptolib (47fac86058f60ab78dfa277c4c433692f2da1c84), AES-KWP exp_pad size standardization and DRBG buffer sizing (4cb47230d01ac2dff589b22a85de6e623cc2aafc, 75f7d2fe44f2e3da01511f8d4f0a4c6e0cbbdd64), and AES-GCM tag length check (ee4aad73d4a193892cb6f8baa2354ec333dacaea). Impact: strengthened resistance to fault injections, safer release builds, and improved reliability and performance in critical crypto paths. Value: reduces deployment risk and reinforces cryptographic guarantees in OT repositories.
April 2026
March 2026
28 Commits • 14 Features
Mar 1, 2026March 2026 monthly work summary for lowRISC/opentitan focused on security buffer improvements, test infrastructure, and crypto library robustness. Delivered new tests and macros, strengthened cryptographic buffer handling, and expanded cryptographic test coverage to improve reliability and security posture.
March 2026
28 Commits • 14 Features
Mar 1, 2026March 2026 monthly work summary for lowRISC/opentitan focused on security buffer improvements, test infrastructure, and crypto library robustness. Delivered new tests and macros, strengthened cryptographic buffer handling, and expanded cryptographic test coverage to improve reliability and security posture.
February 2026
5 Commits • 3 Features
Feb 1, 2026February 2026 deliverables centered on strengthening the reliability of the Penetration Testing framework and reinforcing cryptographic data integrity in opentitan. Notable work includes fixes to the firmware override RNG test to run reliably without device resets, enhancements to KMAC/SHA3 testing, and integration of pointer-level integrity checks across DRBG, HMAC, and crypto buffers. These changes reduce test flakiness, improve security validation, and broaden testing coverage for cryptographic primitives.
5 Commits • 3 Features
Feb 1, 2026February 2026 deliverables centered on strengthening the reliability of the Penetration Testing framework and reinforcing cryptographic data integrity in opentitan. Notable work includes fixes to the firmware override RNG test to run reliably without device resets, enhancements to KMAC/SHA3 testing, and integration of pointer-level integrity checks across DRBG, HMAC, and crypto buffers. These changes reduce test flakiness, improve security validation, and broaden testing coverage for cryptographic primitives.
February 2026
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for lowRISC/opentitan. Focused on stabilizing long-running pentest workflows by enhancing UART readouts. Delivered an initial timeout option for the read_response function to accommodate tests where operational time exceeds UART response time, reducing flakiness and enabling batched tests. Core change implemented in the pentest framework with commit 8ead9103b29be87a7d3c4009a6355ccfa7f1a869; Signed-off-by: Siemen Dhooghe. Overall impact includes more reliable data collection during security assessments and smoother automation of extended tests.
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for lowRISC/opentitan. Focused on stabilizing long-running pentest workflows by enhancing UART readouts. Delivered an initial timeout option for the read_response function to accommodate tests where operational time exceeds UART response time, reducing flakiness and enabling batched tests. Core change implemented in the pentest framework with commit 8ead9103b29be87a7d3c4009a6355ccfa7f1a869; Signed-off-by: Siemen Dhooghe. Overall impact includes more reliable data collection during security assessments and smoother automation of extended tests.
December 2025
16 Commits • 5 Features
Dec 1, 2025Month: 2025-12 summary for lowRISC/opentitan focusing on ROM security validation, debugger reliability, and CI-friendly testing. Key accomplishments include: (1) ROM_EXT security testing framework and ROM_EXT secure boot validation, with rollback/version checks, fault-injection readiness, new test targets, GDB tracing, and test harness enhancements (plus ROM footprint optimization by disabling compiler jump guards). (2) OpenOCD/Debugger reliability improvements: corrected end-byte handling, ability to halt the CPU during reset, and improved labels/data reading. (3) FiSim and GDB testing improvements: unit tests for FiSim and updated logging for CI. (4) Cryptography alerting and robustness: added cryptolib alert outputs and wrapper-based alert handling to ensure alerts surface in tests. (5) Target and assembly reliability improvements: higher pacing to reduce flakiness and added clobbered registers.
16 Commits • 5 Features
Dec 1, 2025Month: 2025-12 summary for lowRISC/opentitan focusing on ROM security validation, debugger reliability, and CI-friendly testing. Key accomplishments include: (1) ROM_EXT security testing framework and ROM_EXT secure boot validation, with rollback/version checks, fault-injection readiness, new test targets, GDB tracing, and test harness enhancements (plus ROM footprint optimization by disabling compiler jump guards). (2) OpenOCD/Debugger reliability improvements: corrected end-byte handling, ability to halt the CPU during reset, and improved labels/data reading. (3) FiSim and GDB testing improvements: unit tests for FiSim and updated logging for CI. (4) Cryptography alerting and robustness: added cryptolib alert outputs and wrapper-based alert handling to ensure alerts surface in tests. (5) Target and assembly reliability improvements: higher pacing to reduce flakiness and added clobbered registers.
December 2025
November 2025
24 Commits • 6 Features
Nov 1, 2025Month: 2025-11 Concise monthly summary focusing on business value and technical achievements for lowRISC/opentitan.
November 2025
24 Commits • 6 Features
Nov 1, 2025Month: 2025-11 Concise monthly summary focusing on business value and technical achievements for lowRISC/opentitan.
October 2025
1 Commits • 1 Features
Oct 1, 2025Monthly summary for 2025-10: Delivered targeted CW340 FPGA penetration-testing enhancements in opentitan, enabling GDB-based testing of the CW340 RMA lifecycle. Implemented a new pentest target (fpga_cw340_rom_ext) and updated the build/configuration to register and expose it within the existing test harness. This expands hardware test coverage, shortens validation cycles, and improves early detection of regressions in FPGA firmware/RTL interactions.
1 Commits • 1 Features
Oct 1, 2025Monthly summary for 2025-10: Delivered targeted CW340 FPGA penetration-testing enhancements in opentitan, enabling GDB-based testing of the CW340 RMA lifecycle. Implemented a new pentest target (fpga_cw340_rom_ext) and updated the build/configuration to register and expose it within the existing test harness. This expands hardware test coverage, shortens validation cycles, and improves early detection of regressions in FPGA firmware/RTL interactions.
October 2025
September 2025
16 Commits • 2 Features
Sep 1, 2025September 2025 (2025-09) achievements in lowRISC/opentitan focused on security hardening, testability, and reliability. Delivered a Python-based penetration testing framework with cryptolib test integration, expanded test scripts/build targets, and improved testing infrastructure; implemented comprehensive cryptographic library hardening to mitigate side-channel and fault attacks, including hardened macros, launder functions, and checksum verifications. Fixed a critical alert handling bug in penetration testing firmware to ensure alerts remain properly unconfigured when disabled. These efforts collectively reduce risk in security-critical firmware, accelerate validation cycles, and demonstrate strong cross-disciplinary skills in software, cryptography, hardware-test tooling, and CI workflows.
September 2025
16 Commits • 2 Features
Sep 1, 2025September 2025 (2025-09) achievements in lowRISC/opentitan focused on security hardening, testability, and reliability. Delivered a Python-based penetration testing framework with cryptolib test integration, expanded test scripts/build targets, and improved testing infrastructure; implemented comprehensive cryptographic library hardening to mitigate side-channel and fault attacks, including hardened macros, launder functions, and checksum verifications. Fixed a critical alert handling bug in penetration testing firmware to ensure alerts remain properly unconfigured when disabled. These efforts collectively reduce risk in security-critical firmware, accelerate validation cycles, and demonstrate strong cross-disciplinary skills in software, cryptography, hardware-test tooling, and CI workflows.
August 2025
4 Commits • 1 Features
Aug 1, 2025Month: 2025-08 — LowRISC/opentitan: Delivered consolidated Penetration Testing Enhancements across hardware alerts, crypto tests, FPGA compatibility, and test reliability. Implemented configurable AES test inputs in crypto_fi, adjusted pentest init to disable flash fatal alerts for FPGA compatibility, and aligned random value generation in Ibex SCA tests to improve reliability and comparability. These changes broaden security coverage, improve test reliability across platforms, and accelerate cross-hardware validation, supporting higher confidence in hardware/firmware security before release.
4 Commits • 1 Features
Aug 1, 2025Month: 2025-08 — LowRISC/opentitan: Delivered consolidated Penetration Testing Enhancements across hardware alerts, crypto tests, FPGA compatibility, and test reliability. Implemented configurable AES test inputs in crypto_fi, adjusted pentest init to disable flash fatal alerts for FPGA compatibility, and aligned random value generation in Ibex SCA tests to improve reliability and comparability. These changes broaden security coverage, improve test reliability across platforms, and accelerate cross-hardware validation, supporting higher confidence in hardware/firmware security before release.
August 2025
July 2025
29 Commits • 19 Features
Jul 1, 2025July 2025 monthly summary for lowRISC/opentitan focused on delivering cryptographic capability, expanding test coverage, and strengthening CI/build integrity, while improving test determinism and resilience. Key work spanned feature scaffolding, broader cryptographic targets, test instrumentation, and observability enhancements that collectively increase security, reliability, and engineering velocity.
July 2025
29 Commits • 19 Features
Jul 1, 2025July 2025 monthly summary for lowRISC/opentitan focused on delivering cryptographic capability, expanding test coverage, and strengthening CI/build integrity, while improving test determinism and resilience. Key work spanned feature scaffolding, broader cryptographic targets, test instrumentation, and observability enhancements that collectively increase security, reliability, and engineering velocity.
June 2025
5 Commits • 2 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for lowRISC/opentitan: Key features delivered include Sensor Control and Alert Integration in the Pentest Framework and Cryptographic Test Framework Enhancements with modularization and FvsR testing. No explicit critical bugs fixed this month; focus was on architecture, test coverage, and framework improvements that enable scalable security validation. Overall impact: broadened test coverage, reduced risk in sensor/alert handling, and established a scalable cryptographic testing foundation across multiple curves.
5 Commits • 2 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for lowRISC/opentitan: Key features delivered include Sensor Control and Alert Integration in the Pentest Framework and Cryptographic Test Framework Enhancements with modularization and FvsR testing. No explicit critical bugs fixed this month; focus was on architecture, test coverage, and framework improvements that enable scalable security validation. Overall impact: broadened test coverage, reduced risk in sensor/alert handling, and established a scalable cryptographic testing foundation across multiple curves.
June 2025
May 2025
5 Commits • 1 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on key accomplishments, major bugs fixed, and business value for lowRISC/opentitan. Delivered enhancements to the Penetration Testing Framework and a critical firmware test bug fix, resulting in stronger security validation and faster feedback loops.
May 2025
5 Commits • 1 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on key accomplishments, major bugs fixed, and business value for lowRISC/opentitan. Delivered enhancements to the Penetration Testing Framework and a critical firmware test bug fix, resulting in stronger security validation and faster feedback loops.
April 2025
1 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for lowRISC/opentitan. Focused on enhancing ROM_EXT signature verification to strengthen boot-time security and reliability, with minimal impact to release cadence.
1 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for lowRISC/opentitan. Focused on enhancing ROM_EXT signature verification to strengthen boot-time security and reliability, with minimal impact to release cadence.
April 2025
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Quality Metrics
Correctness91.4%
Maintainability87.0%
Architecture87.2%
Performance81.6%
AI Usage22.8%
Skills & Technologies
Programming Languages
AssemblyBUILDBazelCC++JSONMarkdownPythonRustStarlark
Technical Skills
API DevelopmentAssembly LanguageAssembly Language OptimizationAssembly Language ProgrammingBazel build systemBug FixingBuild System ConfigurationBuild SystemsC ProgrammingC programmingC++ programmingCI integrationCI/CDCode FormattingCode Refactoring
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