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Stefan Berger

PROFILE

Stefan Berger

Over four months, this developer contributed to the openssl/openssl and espressif/qemu repositories, focusing on cryptographic feature development, security policy enforcement, and CI stability. They implemented hashless CMS signing and verification, expanded multi-scheme support, and enforced RFC-compliant hash policies using C and Perl. Their work included refactoring signature verification flows, clarifying documentation for Ed448 and Ed25519, and aligning OpenSSL’s CMS handling with security standards. In espressif/qemu, they improved CI reliability by adapting TPM state handling for AppArmor compatibility using Python scripting and system administration skills. Their contributions emphasized maintainability, compliance, and robust, testable code changes.

Overall Statistics

Feature vs Bugs

80%Features

Repository Contributions

9Total
Bugs
1
Commits
9
Features
4
Lines of code
630
Activity Months4

Your Network

607 people

Same Organization

@linux.ibm.com
83
Aboorva DevarajanMember
Aditya BodkheMember
Aditya GuptaMember
Abhishek DubeyMember
Alexander GordeevMember
Andrew DonnellanMember
Aleksei NikiforovMember
Farhan AliMember
Amit MachhiwalMember

Work History

March 2026

3 Commits • 2 Features

Mar 1, 2026

Concise monthly summary for 2026-03 focusing on OpenSSL/openssl repository. Two CMS-related changes were delivered with documentation clarifications and RFC 8419-aligned security policy, improving security posture, interoperability, and developer guidance. Key changes include Ed448 documentation clarifications noting lack of support for CMS with signed attributes due to missing digest algorithm support and id-shake256-len, and the enforcement of SHA-512 as the mandatory hash for CMS signed-data with Ed25519 (with updates to the key2data table). The work involved cross-team reviews and merges in March 2026, reinforcing RFC alignment and maintainability.

November 2025

1 Commits • 1 Features

Nov 1, 2025

Month 2025-11: Feature-focused delivery in openssl/openssl with a targeted improvement to signature handling and CMS verification flow. Implemented message-update capability checks in EVP_PKEY and simplified CMS verification path to streamline signing workflows and future maintenance.

October 2025

4 Commits • 1 Features

Oct 1, 2025

October 2025: Delivered end-to-end hashless (no-attribute) signing support in CMS for openssl/openssl, including signing, verification, and testing. Expanded multi-scheme support to ML-DSA, SLH-DSA, and EdDSA; implemented a default hash policy for hashless signing to ensure correct behavior with and without signed attributes; added comprehensive tests and memory-efficient signing paths.

November 2024

1 Commits

Nov 1, 2024

Monthly summary for 2024-11 focusing on stabilizing test environments and delivering targeted fixes in espressif/qemu to improve CI reliability and test stability. Delivered a security-conscious, AppArmor-compatible TPM state handling change that prevents functional-test failures in restricted directories, with a concise, auditable commit trail for future reviews.

Activity

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Quality Metrics

Correctness95.6%
Maintainability88.8%
Architecture95.6%
Performance86.6%
AI Usage20.0%

Skills & Technologies

Programming Languages

CPerlPython

Technical Skills

C programmingOpenSSLPerlPython ScriptingSystem AdministrationTestingcryptographydocumentationsoftware developmenttesting

Repositories Contributed To

2 repos

Overview of all repositories you've contributed to across your timeline

openssl/openssl

Oct 2025 Mar 2026
3 Months active

Languages Used

CPerl

Technical Skills

C programmingPerlcryptographysoftware developmenttestingOpenSSL

espressif/qemu

Nov 2024 Nov 2024
1 Month active

Languages Used

Python

Technical Skills

Python ScriptingSystem AdministrationTesting