openssl/openssl
Sep 2025 – Mar 2026
7 Months active
Languages Used
CMarkdownPodPerlAssembly
Technical Skills
API designC programmingCryptographySecurityTestingC Development
Daniel Kubec
PROFILE
Daniel Kubec
Over seven months, contributed to the openssl/openssl repository by delivering security-focused enhancements and robust bug fixes across cryptographic, SSL/TLS, and certificate validation components. Developed new APIs for ALPN protocol retrieval and TLS 1.3 signature algorithm reporting, while hardening X.509 and CRL validation to meet RFC 5280 compliance. Addressed vulnerabilities such as CVE-2025-15468 and CVE-2026-28388 through careful error handling and regression testing. Improved thread safety, modularity, and documentation clarity, and streamlined build configurations. Leveraged C and Perl for low-level programming, cryptography, and cross-platform development, consistently prioritizing reliability, maintainability, and secure protocol implementation in complex security-critical code.
Overall Statistics
Feature vs Bugs
50%Features
Repository Contributions
27Total
Bugs
10
Commits
27
Features
10
Lines of code
2,798
Activity Months7
Your Network
380 peopleShared Repositories
365
Work History
March 2026
6 Commits • 2 Features
Mar 1, 2026March 2026 OpenSSL work focused on hardening X.509 verification, Delta CRL robustness, AES-CFB-128 safety, and TLS session handling. Delivered security fixes, robustness improvements, and improved certificate verification while preserving compatibility. Business value includes reduced CVE exposure, more reliable TLS across edge cases, and stronger crypto-path integrity.
6 Commits • 2 Features
Mar 1, 2026March 2026 OpenSSL work focused on hardening X.509 verification, Delta CRL robustness, AES-CFB-128 safety, and TLS session handling. Delivered security fixes, robustness improvements, and improved certificate verification while preserving compatibility. Business value includes reduced CVE exposure, more reliable TLS across edge cases, and stronger crypto-path integrity.
March 2026
February 2026
5 Commits • 3 Features
Feb 1, 2026February 2026 monthly summary for openssl/openssl focused on strengthening PKI validation, improving TLS 1.3 usability, and enhancing documentation. Key features delivered include RFC 5280-compliant AKID verification for X.509 certificates (activated under X509_V_FLAG_X509_STRICT), with explicit error handling for missing or mismatched AKID attributes. Also introduced TLS 1.3 signature algorithm reporting functions for accurate scheme reporting. In addition, CHANGES.md formatting/readability improvements were implemented to improve changelog clarity.
February 2026
5 Commits • 3 Features
Feb 1, 2026February 2026 monthly summary for openssl/openssl focused on strengthening PKI validation, improving TLS 1.3 usability, and enhancing documentation. Key features delivered include RFC 5280-compliant AKID verification for X.509 certificates (activated under X509_V_FLAG_X509_STRICT), with explicit error handling for missing or mismatched AKID attributes. Also introduced TLS 1.3 signature algorithm reporting functions for accurate scheme reporting. In addition, CHANGES.md formatting/readability improvements were implemented to improve changelog clarity.
January 2026
7 Commits • 3 Features
Jan 1, 2026January 2026: OpenSSL improvements focusing on security, API usability, and maintenance. Delivered ALPN protocol list retrieval API, enabling apps to fetch ALPN protocol lists from SSL_CTX and SSL structures. Removed darwin-i386 build targets to streamline configurations. Enhanced app data handling by documenting EVP_CIPHER_CTX_get/set_app_data and EVP_PKEY_CTX_get/set_app_data. Fixed security vulnerability CVE-2025-15468 with a NULL pointer guard in ossl_quic_get_cipher_by_char. Improved CRL handling with ASN.1 parsing error handling improvements and corrected AKID serial number conversion; added early error rejection in crl_set_issuers. These changes boost security, interoperability, and developer productivity while reducing maintenance burden.
7 Commits • 3 Features
Jan 1, 2026January 2026: OpenSSL improvements focusing on security, API usability, and maintenance. Delivered ALPN protocol list retrieval API, enabling apps to fetch ALPN protocol lists from SSL_CTX and SSL structures. Removed darwin-i386 build targets to streamline configurations. Enhanced app data handling by documenting EVP_CIPHER_CTX_get/set_app_data and EVP_PKEY_CTX_get/set_app_data. Fixed security vulnerability CVE-2025-15468 with a NULL pointer guard in ossl_quic_get_cipher_by_char. Improved CRL handling with ASN.1 parsing error handling improvements and corrected AKID serial number conversion; added early error rejection in crl_set_issuers. These changes boost security, interoperability, and developer productivity while reducing maintenance burden.
January 2026
December 2025
2 Commits • 1 Features
Dec 1, 2025December 2025 performance summary for openssl/openssl focusing on security, reliability, and maintainability. Delivered two core changes: ASN.1 BIGNUM positivity validation to reject negative values during parsing, addressing data integrity concerns and negative BIGNUM handling issues; and SSL module thread-safety improvements by removing global data to enhance concurrency safety and modularity, complemented by documentation cleanup to clarify configuration scope and usage. These efforts improve reliability in multi-threaded environments, reduce risk of data corruption, and improve maintainability through clearer docs and reviewer feedback.
December 2025
2 Commits • 1 Features
Dec 1, 2025December 2025 performance summary for openssl/openssl focusing on security, reliability, and maintainability. Delivered two core changes: ASN.1 BIGNUM positivity validation to reject negative values during parsing, addressing data integrity concerns and negative BIGNUM handling issues; and SSL module thread-safety improvements by removing global data to enhance concurrency safety and modularity, complemented by documentation cleanup to clarify configuration scope and usage. These efforts improve reliability in multi-threaded environments, reduce risk of data corruption, and improve maintainability through clearer docs and reviewer feedback.
November 2025
4 Commits • 1 Features
Nov 1, 2025November 2025 (openssl/openssl): Delivered security-focused CRL validation hardening and per-context SSL configuration management. Hardened CRL handling to RFC-5280 compliance and prevented the use of invalid CRLs, while introducing per-OpenSSL-libctx configurations to manage SSL settings across multiple contexts. These changes reduce verification risk, improve deployment flexibility, and enhance maintainability. The work involved code changes, CHANGES.md updates, and cross-team reviews across two major commits and associated PRs.
4 Commits • 1 Features
Nov 1, 2025November 2025 (openssl/openssl): Delivered security-focused CRL validation hardening and per-context SSL configuration management. Hardened CRL handling to RFC-5280 compliance and prevented the use of invalid CRLs, while introducing per-OpenSSL-libctx configurations to manage SSL settings across multiple contexts. These changes reduce verification risk, improve deployment flexibility, and enhance maintainability. The work involved code changes, CHANGES.md updates, and cross-team reviews across two major commits and associated PRs.
November 2025
October 2025
1 Commits
Oct 1, 2025October 2025 monthly summary for openssl/openssl focused on security hardening of AEAD decryption. Implemented enforcement of a valid authentication tag before decryption for ChaCha20-Poly1305, CCM, and GCM, improving resistance to tag-less decryption attempts and aligning with authenticated encryption best practices. Added robust error handling so EVP_DecryptFinal_ex() raises an error when the tag is not set, preventing insecure decryption pathways.
October 2025
1 Commits
Oct 1, 2025October 2025 monthly summary for openssl/openssl focused on security hardening of AEAD decryption. Implemented enforcement of a valid authentication tag before decryption for ChaCha20-Poly1305, CCM, and GCM, improving resistance to tag-less decryption attempts and aligning with authenticated encryption best practices. Added robust error handling so EVP_DecryptFinal_ex() raises an error when the tag is not set, preventing insecure decryption pathways.
September 2025
2 Commits
Sep 1, 2025September 2025 (openssl/openssl): Security and reliability improvements focused on edge-case handling and cryptographic correctness, backed by regression tests. Key commits include 051108ee53d5b0ff5a125d32acfbc7e20899b022 (EVP_PKEY_can_sign() NULL handling) and 6387ec6d492caffa4c9bc137f1cb6c171366c7c7 (ChaCha20-Poly1305 decryption when the tag is missing). Key features delivered: none user-facing; major impact comes from correctness and security hardening. Major bugs fixed: EVP_PKEY_can_sign() path handling with NULL query result; ChaCha20-Poly1305 decryption behavior when tag is missing, aligning with AES-GCM. Overall impact: reduces cryptographic edge-case risk, improves test coverage and release confidence. Technologies/skills demonstrated: C, OpenSSL EVP APIs, regression testing, security-focused debugging and verification.
2 Commits
Sep 1, 2025September 2025 (openssl/openssl): Security and reliability improvements focused on edge-case handling and cryptographic correctness, backed by regression tests. Key commits include 051108ee53d5b0ff5a125d32acfbc7e20899b022 (EVP_PKEY_can_sign() NULL handling) and 6387ec6d492caffa4c9bc137f1cb6c171366c7c7 (ChaCha20-Poly1305 decryption when the tag is missing). Key features delivered: none user-facing; major impact comes from correctness and security hardening. Major bugs fixed: EVP_PKEY_can_sign() path handling with NULL query result; ChaCha20-Poly1305 decryption behavior when tag is missing, aligning with AES-GCM. Overall impact: reduces cryptographic edge-case risk, improves test coverage and release confidence. Technologies/skills demonstrated: C, OpenSSL EVP APIs, regression testing, security-focused debugging and verification.
September 2025
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Quality Metrics
Correctness99.2%
Maintainability92.6%
Architecture98.6%
Performance93.4%
AI Usage20.8%
Skills & Technologies
Programming Languages
AssemblyCMarkdownPerlPod
Technical Skills
API designC DevelopmentC programmingCryptographyOpenSSLOpenSSL developmentPerl scriptingSSL/TLSSSL/TLS configurationSSL/TLS developmentSecurityTestingbuild systemscode reviewconfiguration management
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline