lowRISC/opentitan
Nov 2024 – May 2026
17 Months active
Languages Used
AssemblyCC++RustPythonBazelBUILDStarlark
Technical Skills
C ProgrammingC/C++Code RefactoringCryptographyDriver DevelopmentEmbedded Systems
Yi-Hsuan Deng
PROFILE
Yi-hsuan Deng
Worked extensively on the lowRISC/opentitan repository, delivering robust firmware, security, and test automation features across embedded systems. Developed dynamic firmware configuration and secure boot flows, leveraging C, Rust, and Bazel to improve maintainability and reliability. Enhanced memory safety, cryptographic validation, and coverage instrumentation, introducing modular build systems and automated test suites for end-to-end validation. Addressed critical bugs in SRAM provisioning and bootloader logic, while expanding observability through UART-based debugging and LLVM coverage integration. Demonstrated disciplined code hygiene and CI optimization, enabling reproducible builds and efficient hardware-software integration. The work consistently strengthened system security, test coverage, and downstream customization support.
Overall Statistics
Feature vs Bugs
79%Features
Repository Contributions
138Total
Bugs
12
Commits
138
Features
44
Lines of code
12,208
Activity Months17
Your Network
5101 peopleSame Organization
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Benedict OdaiMember
Craig IngramMember
KayyuriMember
Scott SuarezMember
Agent2Agent (A2A) BotMember
Andreas AbelMember
Aadi KapurMember
Aadish GoelMember
Aahil MehtaMember
Work History
May 2026
5 Commits • 2 Features
May 1, 2026May 2026 monthly summary for lowRISC/opentitan focusing on SRAM reliability, E2E testing, and CI/test scheduling improvements. Key outcomes: corrected SRAM initialization ordering; added SRAM key renewal end-to-end test; hardened FPGA test scheduling by enforcing unique job IDs; and CI optimization by filtering empty FPGA jobs. These changes improved hardware-software integration, test reliability, and CI efficiency, delivering measurable business value and safer production deployments.
5 Commits • 2 Features
May 1, 2026May 2026 monthly summary for lowRISC/opentitan focusing on SRAM reliability, E2E testing, and CI/test scheduling improvements. Key outcomes: corrected SRAM initialization ordering; added SRAM key renewal end-to-end test; hardened FPGA test scheduling by enforcing unique job IDs; and CI optimization by filtering empty FPGA jobs. These changes improved hardware-software integration, test reliability, and CI efficiency, delivering measurable business value and safer production deployments.
May 2026
April 2026
5 Commits • 2 Features
Apr 1, 2026April 2026 monthly summary highlighting key features delivered, major bugs fixed, and overall impact for lowRISC/opentitan. Focused on reliability of Rescue flow, CI efficiency, and demonstrated Rust/clap/Bazel skills with concrete business value.
April 2026
5 Commits • 2 Features
Apr 1, 2026April 2026 monthly summary highlighting key features delivered, major bugs fixed, and overall impact for lowRISC/opentitan. Focused on reliability of Rescue flow, CI efficiency, and demonstrated Rust/clap/Bazel skills with concrete business value.
March 2026
1 Commits • 1 Features
Mar 1, 2026March 2026 (2026-03) monthly summary for lowRISC/opentitan: Delivered a new Quit command for cryptotest to signal host-test completion and trigger a graceful device shutdown, enabling reliable coverage report transfer and a faster feedback loop.
1 Commits • 1 Features
Mar 1, 2026March 2026 (2026-03) monthly summary for lowRISC/opentitan: Delivered a new Quit command for cryptotest to signal host-test completion and trigger a graceful device shutdown, enabling reliable coverage report transfer and a faster feedback loop.
March 2026
February 2026
3 Commits • 2 Features
Feb 1, 2026February 2026: Strengthened coverage fidelity and middleware maintainability in lowRISC/opentitan. Delivered end-to-end coverage collection across UART/Console and RPC, introduced a dedicated CoverageMiddleware to extract and persist LLVM coverage data, and consolidated middleware boilerplate to simplify wrapper implementations. These changes improve test visibility, reliability, and developer productivity, enabling faster validation of hardware/software changes.
February 2026
3 Commits • 2 Features
Feb 1, 2026February 2026: Strengthened coverage fidelity and middleware maintainability in lowRISC/opentitan. Delivered end-to-end coverage collection across UART/Console and RPC, introduced a dedicated CoverageMiddleware to extract and persist LLVM coverage data, and consolidated middleware boilerplate to simplify wrapper implementations. These changes improve test visibility, reliability, and developer productivity, enabling faster validation of hardware/software changes.
January 2026
5 Commits • 2 Features
Jan 1, 2026January 2026: Boot reliability improvements, SKU customization for ROM_EXT, and security hardening for OpenTitan. Delivered provisioned default boot data to ensure bootability when OTP default boot data is disabled; postponed DICE chain initialization to rom_ext_boot to improve reliability and enable rescue mode. Introduced SKU-specific ownership defaults and a SKU init hook to support downstream ROM_EXT builds. Hardened ROM_EXT security with a minimum security version self-check. These changes enable downstream SKUs with configurable defaults, improve boot resilience, and strengthen secure boot, delivering business value through reduced field failures and accelerated downstream integration.
5 Commits • 2 Features
Jan 1, 2026January 2026: Boot reliability improvements, SKU customization for ROM_EXT, and security hardening for OpenTitan. Delivered provisioned default boot data to ensure bootability when OTP default boot data is disabled; postponed DICE chain initialization to rom_ext_boot to improve reliability and enable rescue mode. Introduced SKU-specific ownership defaults and a SKU init hook to support downstream ROM_EXT builds. Hardened ROM_EXT security with a minimum security version self-check. These changes enable downstream SKUs with configurable defaults, improve boot resilience, and strengthen secure boot, delivering business value through reduced field failures and accelerated downstream integration.
January 2026
November 2025
1 Commits • 1 Features
Nov 1, 2025Month: 2025-11 — Focused on feature delivery and debugging observability for the boot path in lowRISC/opentitan. Key feature delivered: Boot Process Debug Information over UART, which prints owner_block config versions during ROM_EXT boot to assist debugging owner_block issues. No major bugs fixed this month. Overall impact: improved boot-time visibility, faster diagnosis of owner_block issues, and strengthened repository quality via standard change-id/cherry-pick workflow. Technologies/skills demonstrated: UART-based boot sequence instrumentation, ROM_EXT boot telemetry, Change-Id-aware cherry-picking, signed-off commits, and cross-team collaboration.
November 2025
1 Commits • 1 Features
Nov 1, 2025Month: 2025-11 — Focused on feature delivery and debugging observability for the boot path in lowRISC/opentitan. Key feature delivered: Boot Process Debug Information over UART, which prints owner_block config versions during ROM_EXT boot to assist debugging owner_block issues. No major bugs fixed this month. Overall impact: improved boot-time visibility, faster diagnosis of owner_block issues, and strengthened repository quality via standard change-id/cherry-pick workflow. Technologies/skills demonstrated: UART-based boot sequence instrumentation, ROM_EXT boot telemetry, Change-Id-aware cherry-picking, signed-off commits, and cross-team collaboration.
October 2025
29 Commits • 5 Features
Oct 1, 2025Monthly summary for 2025-10 (lowRISC/opentitan): Delivered end-to-end assembly code coverage capabilities and reinforced repository-wide instrumentation to improve test visibility and regression confidence. The work focused on expanding the coverage framework (assembly and ROM_EXT paths) and strengthening tooling, CI checks, and documentation to enable reliable LLVM-cov reporting and actionable coverage data across critical sectors of the project.
29 Commits • 5 Features
Oct 1, 2025Monthly summary for 2025-10 (lowRISC/opentitan): Delivered end-to-end assembly code coverage capabilities and reinforced repository-wide instrumentation to improve test visibility and regression confidence. The work focused on expanding the coverage framework (assembly and ROM_EXT paths) and strengthening tooling, CI checks, and documentation to enable reliable LLVM-cov reporting and actionable coverage data across critical sectors of the project.
October 2025
September 2025
8 Commits • 6 Features
Sep 1, 2025September 2025 monthly summary focusing on reliability, modularity, and coverage instrumentation across the lowRISC/opentitan repository. Delivered updates to test configuration, Bazel-based build and coverage tooling, and cryptographic operation safety, enabling faster CI feedback and improved observability.
September 2025
8 Commits • 6 Features
Sep 1, 2025September 2025 monthly summary focusing on reliability, modularity, and coverage instrumentation across the lowRISC/opentitan repository. Delivered updates to test configuration, Bazel-based build and coverage tooling, and cryptographic operation safety, enabling faster CI feedback and improved observability.
August 2025
6 Commits • 3 Features
Aug 1, 2025August 2025 monthly summary for opentitan: Delivered core improvements in firmware configurability, memory safety, and ROM test coverage. Implemented Dynamic Firmware Configuration System using Bazel variables and dynamic linker/script configurations to consolidate slot management and reduce hard-coded addresses, enabling easier maintenance across firmware builds. Fixed a critical memory safety issue in SRAM provisioning by adding a stack/BSS boundary check, preventing overflow and improving robustness. Expanded test coverage for OTP-driven ROM behavior with end-to-end tests for clock jitter switches and for OTP-controlled debug information, and extended CRT test suite with corner-case trapping and an illegal-instruction fault handler. These changes enhance reliability and maintainability across builds. Commits include: ddedbfe8b6a955a4ab2073e4b43726d0f6962b77; 535c83a375ca2ecf9792e87185a402adeb14a91a; 98087420e536f7e6e3e62c2540a777bb199cea6f; d55f82b2973b3c0cfad258c12ac0c7ebd0032e36; 22b82b7a41449d579f6487af603505b1c6fdb80f; 38bdc708ab5e183188a6f506c2972e7239002128.
6 Commits • 3 Features
Aug 1, 2025August 2025 monthly summary for opentitan: Delivered core improvements in firmware configurability, memory safety, and ROM test coverage. Implemented Dynamic Firmware Configuration System using Bazel variables and dynamic linker/script configurations to consolidate slot management and reduce hard-coded addresses, enabling easier maintenance across firmware builds. Fixed a critical memory safety issue in SRAM provisioning by adding a stack/BSS boundary check, preventing overflow and improving robustness. Expanded test coverage for OTP-driven ROM behavior with end-to-end tests for clock jitter switches and for OTP-controlled debug information, and extended CRT test suite with corner-case trapping and an illegal-instruction fault handler. These changes enhance reliability and maintainability across builds. Commits include: ddedbfe8b6a955a4ab2073e4b43726d0f6962b77; 535c83a375ca2ecf9792e87185a402adeb14a91a; 98087420e536f7e6e3e62c2540a777bb199cea6f; d55f82b2973b3c0cfad258c12ac0c7ebd0032e36; 22b82b7a41449d579f6487af603505b1c6fdb80f; 38bdc708ab5e183188a6f506c2972e7239002128.
August 2025
July 2025
11 Commits • 4 Features
Jul 1, 2025July 2025 performance summary for lowRISC/opentitan focused on increasing test automation, debugging capabilities, and cryptographic validation for OTBN. Delivered consolidated OTBN testing and simulation tooling, extended DMEM memory loading capabilities, and enhanced simulator observability. Expanded P-256 cryptography test coverage, and implemented a critical endianness fix to improve numeric correctness across simulations. These efforts bolster validation throughput, reduce verification risk, and demonstrate strong engineering discipline across testing, debugging, and cryptographic verification.
July 2025
11 Commits • 4 Features
Jul 1, 2025July 2025 performance summary for lowRISC/opentitan focused on increasing test automation, debugging capabilities, and cryptographic validation for OTBN. Delivered consolidated OTBN testing and simulation tooling, extended DMEM memory loading capabilities, and enhanced simulator observability. Expanded P-256 cryptography test coverage, and implemented a critical endianness fix to improve numeric correctness across simulations. These efforts bolster validation throughput, reduce verification risk, and demonstrate strong engineering discipline across testing, debugging, and cryptographic verification.
June 2025
15 Commits • 4 Features
Jun 1, 2025June 2025 monthly summary for lowRISC/opentitan focused on delivering secure, reliable firmware features and expanding end-to-end validation. Highlights include CDI data integrity and signing improvements, DICE page integrity enhancements, rescue mode reliability improvements, and broadened end-to-end boot service test coverage. These efforts reduce field risk, improve security guarantees, and strengthen overall system trust and maintainability.
15 Commits • 4 Features
Jun 1, 2025June 2025 monthly summary for lowRISC/opentitan focused on delivering secure, reliable firmware features and expanding end-to-end validation. Highlights include CDI data integrity and signing improvements, DICE page integrity enhancements, rescue mode reliability improvements, and broadened end-to-end boot service test coverage. These efforts reduce field risk, improve security guarantees, and strengthen overall system trust and maintainability.
June 2025
April 2025
6 Commits • 2 Features
Apr 1, 2025April 2025 (2025-04) OpenTitan development focused on strengthening ownership key security for RomExt and expanding validation coverage. Key features delivered include cross-page key algorithm verification to prevent algorithm confusion attacks and alignment of unlock requests with key algorithms, alongside expanded RomExt ownership key handling tests and end-to-end validation using SPX+ keys.
April 2025
6 Commits • 2 Features
Apr 1, 2025April 2025 (2025-04) OpenTitan development focused on strengthening ownership key security for RomExt and expanding validation coverage. Key features delivered include cross-page key algorithm verification to prevent algorithm confusion attacks and alignment of unlock requests with key algorithms, alongside expanded RomExt ownership key handling tests and end-to-end validation using SPX+ keys.
March 2025
18 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for lowRISC/opentitan: Key security hardening, attestation refinements, and release tooling enhancements. Delivered boot-time security hardening and attestation handling updates, plus ROM_EXT imm_section refactor, version stamping, and release tooling. Improved build/test hygiene, reproducible releases, and auditability with commit-stamped artifacts and standardized naming.
18 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for lowRISC/opentitan: Key security hardening, attestation refinements, and release tooling enhancements. Delivered boot-time security hardening and attestation handling updates, plus ROM_EXT imm_section refactor, version stamping, and release tooling. Improved build/test hygiene, reproducible releases, and auditability with commit-stamped artifacts and standardized naming.
March 2025
February 2025
14 Commits • 3 Features
Feb 1, 2025February 2025 (lowRISC/opentitan) focused on strengthening security, reducing firmware size, and improving build maintainability. Delivered integrated ROM_EXT boot hardening, optimized DICE/CWT certificate handling, and a more modular build system. Addressed a critical build dependency issue to stabilize CI and production pipelines. Result: stronger security posture, smaller footprint, more reliable builds, and scalable certificate/variation support.
February 2025
14 Commits • 3 Features
Feb 1, 2025February 2025 (lowRISC/opentitan) focused on strengthening security, reducing firmware size, and improving build maintainability. Delivered integrated ROM_EXT boot hardening, optimized DICE/CWT certificate handling, and a more modular build system. Addressed a critical build dependency issue to stabilize CI and production pipelines. Result: stronger security posture, smaller footprint, more reliable builds, and scalable certificate/variation support.
January 2025
1 Commits • 1 Features
Jan 1, 2025January 2025 monthly summary for lowRISC/opentitan: Key feature delivered: Toolchain optimization flag handling refactor implementing mutual exclusion between -Os and -Oz and introducing constraints/arguments to manage optimization levels, leading to more predictable, robust toolchain configurations. Major bugs fixed: none reported this month. Overall impact and accomplishments: Increased build stability and reliability, reduced risk of misconfiguration in toolchain flags, enabling repeatable builds for downstream targets. Technologies/skills demonstrated: toolchain flag management, constraint design for configuration options, disciplined commit usage and repository alignment with OpenTitan standards.
1 Commits • 1 Features
Jan 1, 2025January 2025 monthly summary for lowRISC/opentitan: Key feature delivered: Toolchain optimization flag handling refactor implementing mutual exclusion between -Os and -Oz and introducing constraints/arguments to manage optimization levels, leading to more predictable, robust toolchain configurations. Major bugs fixed: none reported this month. Overall impact and accomplishments: Increased build stability and reliability, reduced risk of misconfiguration in toolchain flags, enabling repeatable builds for downstream targets. Technologies/skills demonstrated: toolchain flag management, constraint design for configuration options, disciplined commit usage and repository alignment with OpenTitan standards.
January 2025
December 2024
3 Commits • 1 Features
Dec 1, 20242024-12 monthly summary for lowRISC/opentitan: Delivered ROM Extension Build Optimization and Stability to reduce firmware size and preserve version metadata; fixed RNG polling loop to ensure data_ready condition based on RND_STATUS bit0. These work items improve image size, reliability, and RNG correctness, with clear business value in firmware efficiency and system safety.
December 2024
3 Commits • 1 Features
Dec 1, 20242024-12 monthly summary for lowRISC/opentitan: Delivered ROM Extension Build Optimization and Stability to reduce firmware size and preserve version metadata; fixed RNG polling loop to ensure data_ready condition based on RND_STATUS bit0. These work items improve image size, reliability, and RNG correctness, with clear business value in firmware efficiency and system safety.
November 2024
7 Commits • 3 Features
Nov 1, 2024November 2024 monthly summary for lowRISC/opentitan: delivered security, reliability, and reuse improvements across the ROM and DICE stack, with attention to cross-SKU boot consistency and maintainable architecture. Key features included DICE and certificate handling modernization, an immutable ROM extension boot order, and relocation of the ePMP library to a common drivers area. A critical bug fix addressed DICE page ID handling to ensure correct boot-time behavior. The work strengthens security posture, reduces ROM footprint, and improves reuse and build stability.
7 Commits • 3 Features
Nov 1, 2024November 2024 monthly summary for lowRISC/opentitan: delivered security, reliability, and reuse improvements across the ROM and DICE stack, with attention to cross-SKU boot consistency and maintainable architecture. Key features included DICE and certificate handling modernization, an immutable ROM extension boot order, and relocation of the ePMP library to a common drivers area. A critical bug fix addressed DICE page ID handling to ensure correct boot-time behavior. The work strengthens security posture, reduces ROM footprint, and improves reuse and build stability.
November 2024
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Quality Metrics
Correctness94.8%
Maintainability90.0%
Architecture91.2%
Performance87.0%
AI Usage21.8%
Skills & Technologies
Programming Languages
AssemblyBUILDBashBazelBzlCC++HjsonMakeMakefile
Technical Skills
AssemblyAutomationBackend DevelopmentBazelBazel Build SystemBuild SystemBuild System ConfigurationBuild System ManagementBuild SystemsC PreprocessorC ProgrammingC programmingC++C/C++CI/CD
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline