trezor/trezor-firmware
Jul 2024 – Feb 2026
16 Months active
Languages Used
CPythonProtoBufRustMarkdownJavaScriptMakefileProtocol Buffers
Technical Skills
C programmingPython scriptingembedded systemsfirmware developmentPythonPython development
Andrew Kozlik
PROFILE
Andrew Kozlik
Andrew Kozlik engineered security-critical features and robust cryptographic workflows for the trezor/trezor-firmware repository over 16 months. He delivered enhancements such as entropy validation, ECDSA key masking, and post-quantum attestation, focusing on secure device identity and key management. Using C, Python, and Rust, Andrew implemented cross-coin PaymentRequest support, certificate chain validation, and hardware-backed randomness integration. His technical approach emphasized code hygiene, thorough testing, and detailed documentation, addressing concurrency, error handling, and memory safety. The depth of his work is reflected in seamless firmware-prodtest integration, resilient initialization flows, and maintainable cryptographic APIs, strengthening both reliability and long-term security posture.
Overall Statistics
Feature vs Bugs
76%Features
Repository Contributions
77Total
Bugs
8
Commits
77
Features
26
Lines of code
14,776
Activity Months16
Your Network
38 peopleWork History
February 2026
3 Commits • 1 Features
Feb 1, 2026February 2026: Focused on security hardening and robustness for trezor-firmware. Delivered Tropic signature enforcement and integration of the T3B1 root production key, and improved error handling with memory cleanup/zeroization in hdnode_deserialize, enhancing reliability and security posture across cryptographic operations.
3 Commits • 1 Features
Feb 1, 2026February 2026: Focused on security hardening and robustness for trezor-firmware. Delivered Tropic signature enforcement and integration of the T3B1 root production key, and improved error handling with memory cleanup/zeroization in hdnode_deserialize, enhancing reliability and security posture across cryptographic operations.
February 2026
January 2026
2 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for trezor/trezor-firmware: Delivered a targeted CLI enhancement and resolved a critical concurrency issue, contributing to improved reliability, data visibility, and deployability. The changes delivered tangible business value by enabling safer data access workflows and reducing the risk of production stalls in test and automation environments.
January 2026
2 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for trezor/trezor-firmware: Delivered a targeted CLI enhancement and resolved a critical concurrency issue, contributing to improved reliability, data visibility, and deployability. The changes delivered tangible business value by enabling safer data access workflows and reducing the risk of production stalls in test and automation environments.
December 2025
1 Commits • 1 Features
Dec 1, 2025December 2025: Focused enhancement to prodtest Tropic in trezor-firmware, delivering clearer error handling and user feedback to improve debugging, diagnostics, and test reliability. Implemented detailed error messages across prodtest_tropic.c, enabling quicker triage of test failures and better operator guidance during hardware validation. This work was delivered through a focused core fix (commit 10e195493bd97899555fa9761b0b02b210756e23) with no changelog entry. Impact: reduced mean time to repair (MTTR) for prod test issues, improved maintainability, and stronger validation outcomes. Technologies/skills demonstrated include C firmware development, robust error handling, logging/diagnostics, code quality discipline, and Prodtest tooling.
1 Commits • 1 Features
Dec 1, 2025December 2025: Focused enhancement to prodtest Tropic in trezor-firmware, delivering clearer error handling and user feedback to improve debugging, diagnostics, and test reliability. Implemented detailed error messages across prodtest_tropic.c, enabling quicker triage of test failures and better operator guidance during hardware validation. This work was delivered through a focused core fix (commit 10e195493bd97899555fa9761b0b02b210756e23) with no changelog entry. Impact: reduced mean time to repair (MTTR) for prod test issues, improved maintainability, and stronger validation outcomes. Technologies/skills demonstrated include C firmware development, robust error handling, logging/diagnostics, code quality discipline, and Prodtest tooling.
December 2025
October 2025
4 Commits
Oct 1, 2025Month 2025-10 focused on improving Tropic initialization reliability and session startup stability in trezor-firmware. Delivered two targeted fixes that ensure Tropic is fully booted before session start and stabilized the Tropic initialization flow in production testing environments. Result: higher startup reliability, fewer session-start errors, and more predictable user experiences during device warm-up and testing. Demonstrated strong skills in firmware initialization patterns, robust polling with timeouts, and careful change management through cherry-picks and reverts to maintain production stability.
October 2025
4 Commits
Oct 1, 2025Month 2025-10 focused on improving Tropic initialization reliability and session startup stability in trezor-firmware. Delivered two targeted fixes that ensure Tropic is fully booted before session start and stabilized the Tropic initialization flow in production testing environments. Result: higher startup reliability, fewer session-start errors, and more predictable user experiences during device warm-up and testing. Demonstrated strong skills in firmware initialization patterns, robust polling with timeouts, and careful change management through cherry-picks and reverts to maintain production stability.
September 2025
21 Commits • 2 Features
Sep 1, 2025September 2025 monthly summary for trezor-firmware. Key deliverables focused on ProdTest Tropic integration, Tropic core data handling, and stability improvements that collectively strengthen device trust, certificate workflows, and system reliability. Highlights include expanded ProdTest Tropic session startup with a larger stack for ML-DSA, exposed session factory hooks, and added trusted anchors with certificate chain checks prior to storage. Core Tropic work encompassed correct pairing keys in handshake, AuthenticityProof Tropic field support, Tropic data read/write, certificate handling, and multi-read optimizations, plus Tropic-related refactors (tropic.h) and access controls (authenticateDevice). Provenance and safety enhancements were complemented by legacy fixes for overflows and division-by-zero risks and dedicated ProdTest certificate handling fixes. Overall, these changes improve security posture, reduce risk in onboarding and certificate workflows, and accelerate future Tropic feature delivery.
21 Commits • 2 Features
Sep 1, 2025September 2025 monthly summary for trezor-firmware. Key deliverables focused on ProdTest Tropic integration, Tropic core data handling, and stability improvements that collectively strengthen device trust, certificate workflows, and system reliability. Highlights include expanded ProdTest Tropic session startup with a larger stack for ML-DSA, exposed session factory hooks, and added trusted anchors with certificate chain checks prior to storage. Core Tropic work encompassed correct pairing keys in handshake, AuthenticityProof Tropic field support, Tropic data read/write, certificate handling, and multi-read optimizations, plus Tropic-related refactors (tropic.h) and access controls (authenticateDevice). Provenance and safety enhancements were complemented by legacy fixes for overflows and division-by-zero risks and dedicated ProdTest certificate handling fixes. Overall, these changes improve security posture, reduce risk in onboarding and certificate workflows, and accelerate future Tropic feature delivery.
September 2025
August 2025
7 Commits • 5 Features
Aug 1, 2025Monthly summary for 2025-08: Delivered major hardware security and identity improvements for trezor-firmware. Implemented device identity naming and secret storage layout refinements; expanded production testing with Tropic-backed FIDO attestation read capability; added certificate-based device verification and chain validation during production testing; migrated MCU device attestation keys to ML-DSA-44 (post-quantum capable) with submodule and build/verification updates; integrated Tropic randomness into secret generation, requiring a Tropic factory session. These changes strengthen hardware-backed identity, improve testability, and advance post-quantum readiness, while maintaining build integrity and security best practices.
August 2025
7 Commits • 5 Features
Aug 1, 2025Monthly summary for 2025-08: Delivered major hardware security and identity improvements for trezor-firmware. Implemented device identity naming and secret storage layout refinements; expanded production testing with Tropic-backed FIDO attestation read capability; added certificate-based device verification and chain validation during production testing; migrated MCU device attestation keys to ML-DSA-44 (post-quantum capable) with submodule and build/verification updates; integrated Tropic randomness into secret generation, requiring a Tropic factory session. These changes strengthen hardware-backed identity, improve testability, and advance post-quantum readiness, while maintaining build integrity and security best practices.
June 2025
4 Commits • 2 Features
Jun 1, 2025June 2025 monthly summary for trezor/trezor-firmware focused on security hardening and flexible key-management enhancements. Key features delivered include masking of FIDO attestation keys in both prodtest and firmware to obscure sensitive material during testing and deployment, and master-key-driven secret derivation with pairing secret derivation support within the Secret API and prodtest. No explicit major bug fixes were recorded this month; the work centered on security improvements, API hardening, and refactoring to enable future cryptographic features. Overall impact: reduced risk of sensitive data exposure in testing and firmware, improved cryptographic flexibility and provisioning workflows, and a stronger security posture for device attestation and key management. Technologies/skills demonstrated include macro-controlled masking via SECRET_KEY_MASKING, firmware-prodtest integration, master-key derivation across multiple key types (symmetric, Curve25519, NIST P-256), and key-slot handling refactors to improve security and flexibility.
4 Commits • 2 Features
Jun 1, 2025June 2025 monthly summary for trezor/trezor-firmware focused on security hardening and flexible key-management enhancements. Key features delivered include masking of FIDO attestation keys in both prodtest and firmware to obscure sensitive material during testing and deployment, and master-key-driven secret derivation with pairing secret derivation support within the Secret API and prodtest. No explicit major bug fixes were recorded this month; the work centered on security improvements, API hardening, and refactoring to enable future cryptographic features. Overall impact: reduced risk of sensitive data exposure in testing and firmware, improved cryptographic flexibility and provisioning workflows, and a stronger security posture for device attestation and key management. Technologies/skills demonstrated include macro-controlled masking via SECRET_KEY_MASKING, firmware-prodtest integration, master-key derivation across multiple key types (symmetric, Curve25519, NIST P-256), and key-slot handling refactors to improve security and flexibility.
June 2025
May 2025
2 Commits • 1 Features
May 1, 2025May 2025 Monthly Summary for trezor/trezor-firmware: Delivered ECDSA Key Masking for Secure Key Handling. Implemented masking/unmasking functions for ECDSA private and public keys with validation of masking keys and correct derivation of unmasked values. Added unit tests for masking functionality. This work enhances cryptographic security by reducing exposure of keys during processing and strengthens the product's security posture. Major bugs fixed this month: none reported; primary focus on feature delivery. Commit references: 1ff04d10c6ddf891d36671c976a1a9191242d25b, 2abf41b57cb00505235dad026e4e5e860d512bc3.
May 2025
2 Commits • 1 Features
May 1, 2025May 2025 Monthly Summary for trezor/trezor-firmware: Delivered ECDSA Key Masking for Secure Key Handling. Implemented masking/unmasking functions for ECDSA private and public keys with validation of masking keys and correct derivation of unmasked values. Added unit tests for masking functionality. This work enhances cryptographic security by reducing exposure of keys during processing and strengthens the product's security posture. Major bugs fixed this month: none reported; primary focus on feature delivery. Commit references: 1ff04d10c6ddf891d36671c976a1a9191242d25b, 2abf41b57cb00505235dad026e4e5e860d512bc3.
April 2025
19 Commits • 5 Features
Apr 1, 2025April 2025 for trezor-firmware delivered cross-coin PaymentRequest capabilities, security hardening, and new key-management features. Key work included expanding PaymentRequest across non-Bitcoin-like coins, Ripple/Ethereum integration with signing and verification, address MAC security enhancements, and Cardano SLIP-21 keychain support. The efforts improved interoperability, security, and developer velocity while expanding coin coverage for customers.
19 Commits • 5 Features
Apr 1, 2025April 2025 for trezor-firmware delivered cross-coin PaymentRequest capabilities, security hardening, and new key-management features. Key work included expanding PaymentRequest across non-Bitcoin-like coins, Ripple/Ethereum integration with signing and verification, address MAC security enhancements, and Cardano SLIP-21 keychain support. The efforts improved interoperability, security, and developer velocity while expanding coin coverage for customers.
April 2025
March 2025
5 Commits • 3 Features
Mar 1, 2025March 2025 (trezor-firmware): Focused on security-forward enhancements and thorough documentation to reduce risk during development and strengthen production readiness. Delivered emulator warnings, Optiga PIN protection guidance, and an enhanced entropy-check workflow with GetPublicKey support and tests. No major bugs fixed in this period; ongoing maintenance and quality assurance activities were documented and tested. Business value: clearer guidelines to prevent emulator misuse, stronger cryptographic hygiene, and faster on-boarding for secure Optiga configurations. Technologies/skills: security design, documentation, testing, and integration of key cryptographic checks in ResetDevice flow.
March 2025
5 Commits • 3 Features
Mar 1, 2025March 2025 (trezor-firmware): Focused on security-forward enhancements and thorough documentation to reduce risk during development and strengthen production readiness. Delivered emulator warnings, Optiga PIN protection guidance, and an enhanced entropy-check workflow with GetPublicKey support and tests. No major bugs fixed in this period; ongoing maintenance and quality assurance activities were documented and tested. Business value: clearer guidelines to prevent emulator misuse, stronger cryptographic hygiene, and faster on-boarding for secure Optiga configurations. Technologies/skills: security design, documentation, testing, and integration of key cryptographic checks in ResetDevice flow.
February 2025
1 Commits • 1 Features
Feb 1, 2025February 2025 monthly summary for trezor-firmware: Focused on code hygiene and API clarity. Removed the unused mnemonic_generate() function from trezorcrypto across the C header, C source, and Python interface, eliminating dead code and simplifying the codebase. This reduces maintenance risk and prevents confusion around the API surface. No user-facing features were released this month, but the cleanup improves long-term stability and maintainability of core crypto integrations.
1 Commits • 1 Features
Feb 1, 2025February 2025 monthly summary for trezor-firmware: Focused on code hygiene and API clarity. Removed the unused mnemonic_generate() function from trezorcrypto across the C header, C source, and Python interface, eliminating dead code and simplifying the codebase. This reduces maintenance risk and prevents confusion around the API surface. No user-facing features were released this month, but the cleanup improves long-term stability and maintainability of core crypto integrations.
February 2025
January 2025
1 Commits
Jan 1, 2025January 2025 monthly summary for trezor-firmware: Delivered a targeted fix to ensure batch numbers display correctly in the ProdTest environment by refining the DOM-based extraction and formatting to derive the batch number following the model identifier. This change prevents misreporting of batch data during QA and production validation and reduces downstream rework. The fix is committed in 27ed1fd49e710c2d9bca519255c9caa829a5b7b4 and landed in the ProdTest workflow.
January 2025
1 Commits
Jan 1, 2025January 2025 monthly summary for trezor-firmware: Delivered a targeted fix to ensure batch numbers display correctly in the ProdTest environment by refining the DOM-based extraction and formatting to derive the batch number following the model identifier. This change prevents misreporting of batch data during QA and production validation and reduces downstream rework. The fix is committed in 27ed1fd49e710c2d9bca519255c9caa829a5b7b4 and landed in the ProdTest workflow.
December 2024
1 Commits
Dec 1, 2024December 2024: Stabilized and prepared the core testing infrastructure for trezor-firmware by aligning core test fixtures with recent code changes and setting up for upcoming test cases. This work strengthens test reliability and accelerates safe validation ahead of firmware releases. Commit reference: 57868ad48f4c462bb1f4fa57572067e89a039a60 (chore(core): Update fixtures).
1 Commits
Dec 1, 2024December 2024: Stabilized and prepared the core testing infrastructure for trezor-firmware by aligning core test fixtures with recent code changes and setting up for upcoming test cases. This work strengthens test reliability and accelerates safe validation ahead of firmware releases. Commit reference: 57868ad48f4c462bb1f4fa57572067e89a039a60 (chore(core): Update fixtures).
December 2024
October 2024
1 Commits • 1 Features
Oct 1, 2024October 2024 (2024-10) monthly summary for trezor/trezor-firmware. Focused on expanding automated test coverage for the ResetDevice entropy workflow to improve reliability of entropy initialization and mnemonic handling.
October 2024
1 Commits • 1 Features
Oct 1, 2024October 2024 (2024-10) monthly summary for trezor/trezor-firmware. Focused on expanding automated test coverage for the ResetDevice entropy workflow to improve reliability of entropy initialization and mnemonic handling.
September 2024
4 Commits • 2 Features
Sep 1, 2024Month: 2024-09 — trezor-firmware delivered security-focused enhancements and cryptographic improvements. Key features delivered include: Entropy Check Workflow across seed generation, device reset, and initialization to validate entropy via internal/external sources during cryptographic key generation; and Enhanced Cryptography Packages by adding Shamir-mnemonic and SLIP10 dependencies to bolster cryptographic capabilities. No major bugs fixed this month. Business impact: stronger security posture, more reliable key material generation, and groundwork for compliance and future security features. Technologies demonstrated: cross-layer entropy validation, cryptographic package management, Python/firmware integration, and secure messaging scaffolding.
4 Commits • 2 Features
Sep 1, 2024Month: 2024-09 — trezor-firmware delivered security-focused enhancements and cryptographic improvements. Key features delivered include: Entropy Check Workflow across seed generation, device reset, and initialization to validate entropy via internal/external sources during cryptographic key generation; and Enhanced Cryptography Packages by adding Shamir-mnemonic and SLIP10 dependencies to bolster cryptographic capabilities. No major bugs fixed this month. Business impact: stronger security posture, more reliable key material generation, and groundwork for compliance and future security features. Technologies demonstrated: cross-layer entropy validation, cryptographic package management, Python/firmware integration, and secure messaging scaffolding.
September 2024
July 2024
1 Commits • 1 Features
Jul 1, 2024Month: 2024-07 — Summary: Delivered Secure SCM_REVISION Randomization for firmware builds in trezor-firmware, introducing a dedicated SCM revision handler and updated build scripts to incorporate the new functionality. This feature enhances security and variability of firmware builds, reducing build fingerprinting and improving supply-chain resilience. Commit reference: 83a96f7a5a1dd1cb5e04b0aab74ace151d329eb9.
July 2024
1 Commits • 1 Features
Jul 1, 2024Month: 2024-07 — Summary: Delivered Secure SCM_REVISION Randomization for firmware builds in trezor-firmware, introducing a dedicated SCM revision handler and updated build scripts to incorporate the new functionality. This feature enhances security and variability of firmware builds, reducing build fingerprinting and improving supply-chain resilience. Commit reference: 83a96f7a5a1dd1cb5e04b0aab74ace151d329eb9.
Activity
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Quality Metrics
Correctness92.4%
Maintainability86.0%
Architecture85.8%
Performance81.2%
AI Usage20.0%
Skills & Technologies
Programming Languages
CJavaScriptLinker ScriptMakefileMarkdownProtoBufProtocol BuffersPythonRustprotobuf
Technical Skills
API DesignAPI DevelopmentBIP-32Backend DevelopmentBuild SystemsC ProgrammingC programmingCardanoCode OrganizationCode RefactoringCode WarningsCommand Line Interface DevelopmentCore DevelopmentCross-platform DevelopmentCryptocurrency
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