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Will Childs-Klein

PROFILE

Will Childs-klein

Over 15 months, Chris Child built and enhanced cryptographic and security features in the aws/aws-lc repository, focusing on TLS, PKCS7, and cross-language integration. He implemented BIO filters and PKCS7 data handling, improved compatibility with Python and Ruby, and delivered TLS PSK and P521 support. Using C, C++, and Python, Chris refactored cryptographic APIs, expanded CI coverage, and introduced new test infrastructure for multi-architecture and multi-version validation. His work addressed memory management, security hardening, and protocol flexibility, resulting in a robust, maintainable codebase that supports evolving standards and reliable integration with upstream projects and diverse client environments.

Overall Statistics

Feature vs Bugs

71%Features

Repository Contributions

39Total
Bugs
9
Commits
39
Features
22
Lines of code
12,758
Activity Months15

Work History

March 2026

2 Commits • 2 Features

Mar 1, 2026

March 2026: Key features delivered in aws/aws-lc include client-side TLS post-handshake CA name caching and Ed25519 support via EVP with non-legacy marshal/parse fallbacks. These enhancements improve TLS usability, interoperability, and maintainability.

February 2026

5 Commits • 2 Features

Feb 1, 2026

February 2026 performance and security-focused sprint across aws/s2n-tls and aws/aws-lc. Delivered new cryptographic benchmarking visibility, CI/test automation for PyOpenSSL compatibility, and hardened PKCS7 memory management with regression coverage, aligning with business goals of performance evaluation, reliable CI, and security posture.

January 2026

2 Commits • 2 Features

Jan 1, 2026

Month: 2026-01 — Focused on delivering secure TLS configuration flexibility and strengthening test infrastructure with up-to-date compatibility checks. This period delivered a security posture enhancement for TLS cipher negotiation and improved testing coverage, enabling faster validation of cryptography-related features across two critical repositories.

December 2025

1 Commits • 1 Features

Dec 1, 2025

Delivered cross-architecture integration testing for ACCP on the aarch64 architecture in aws/aws-lc during 2025-12. This work added integration tests to verify compatibility and performance of the Amazon Corretto Crypto Provider across architectures, strengthening release confidence for multi-arch deployments and reducing post-release risk.

November 2025

2 Commits • 1 Features

Nov 1, 2025

November 2025 focus for aws/aws-lc centered on improving test reliability and expanding cryptographic validation capabilities. Key actions included cleaning up the test infrastructure by removing outdated Python build patches and adding AES CFB128 support in the ACVP framework. These changes reduce maintenance overhead, lower test flakiness, and broaden cryptographic validation coverage, contributing to faster risk assessment and release readiness for a critical security library.

October 2025

2 Commits • 1 Features

Oct 1, 2025

In October 2025, delivered security-focused TLS policy and cipher preference improvements across two repos to improve compatibility with legacy TLS versions and provide an opt-out path from post-quantum cryptography. These changes strengthen defense-in-depth for customers with older stacks while maintaining modern cryptography defaults, reduce misconfiguration risk, and demonstrate solid cross-language security engineering (C IO and Java bindings).

September 2025

1 Commits

Sep 1, 2025

September 2025 monthly summary for aws/aws-lc: Focused on stabilizing Python integration tests by pinning the cryptography package to <46 to counter cffi-driven failures, delivering a reliable test baseline ahead of upcoming crypto library changes. This work supports CI stability and upstream reliability for critical cryptography features.

July 2025

5 Commits • 2 Features

Jul 1, 2025

July 2025 performance summary for aws/aws-lc: Focused on security enhancements, CI/test infrastructure improvements, and release readiness. Delivered TLS P521 support in client Hello, enabled dynamic linking in CPython tests, and completed release-prep patches to align with upstream CI and CPython changes. These efforts strengthen protocol security, improve cross-language integration testing, and accelerate the AWS-LC release cycle.

June 2025

2 Commits • 2 Features

Jun 1, 2025

June 2025 monthly summary for aws/aws-lc: Delivered key CI and cryptography enhancements that improve compatibility, testing coverage, and cryptographic capabilities. Key outcomes include: (1) Continuous Integration Enhancement for Multi-Python Testing - expanded CI to run tests across Python 3.13 and 3.14, added a patch for 3.14, and broadened the Python version matrix to improve compatibility with newer releases. (2) HMAC-SHA3 Truncated Variants Support - added HMAC support for truncated SHA3 variants aligned with NIST SP 800-224, refactored HMAC for the SHA3 sponge construction and absence of pre-computed keys, and updated test vectors and service indicators. These changes reduce risk on newer Python releases, extend cryptographic functionality, and improve test signaling. Overall impact: heightened stability across Python environments, compliance with standards, and clearer test feedback. Technologies/skills demonstrated: CI configuration and matrix expansion, Python ecosystem testing, cryptographic API refactoring, test vector management, and verification across multiple variants.

May 2025

3 Commits • 2 Features

May 1, 2025

May 2025 monthly summary for aws/aws-lc: TLS behavior hardening and CI coverage improvements. Delivered a security-conscious flag for TLS 1.3 external PSK support, improved cross-version Python integration, and reduced maintenance by removing an unnecessary patch; results in stronger cross-version reliability and enterprise readiness.

April 2025

2 Commits • 1 Features

Apr 1, 2025

April 2025 (aws/aws-lc): Focused on reliability, visibility, and correctness of OpenSSL-related features in Python SSL workflows. Implemented a new host-flags inspection capability and refined test configuration to reflect AWS-LC limitations, improving integration-test accuracy and CI feedback loops.

January 2025

1 Commits • 1 Features

Jan 1, 2025

January 2025 focused on delivering a feature enhancement in the aws/aws-lc TLS stack: enabling PSK-based certificate-less connections to simplify secure client-server communication where server certificates are not available. This included aligning handshake behavior with Python's TLS implementation by skipping public key loading when a PSK callback is configured, reducing unnecessary cryptographic checks and improving startup performance in PSK-enabled scenarios. Key item: TLS PSK-based certificate-less connections delivered via a4fec0377a11b3ec66e333d8446a5db87568319f ("Allow TLS PSK without server certificate (#2083)"). The work provides a safer, more flexible TLS configuration for clients in environments with PKI constraints while preserving security properties expected from TLS 1.2 PSK mode. There were no major bug fixes published for aws/aws-lc in this period; the month’s focus was feature delivery to expand TLS capabilities and interoperability with CPython behavior.

December 2024

7 Commits • 3 Features

Dec 1, 2024

Month 2024-12 AWS-LC monthly summary focusing on the aws/aws-lc repository. Delivered API improvements, compatibility patches, and cross-platform test updates that reduce risk, improve flexibility across languages (Python, Ruby), and strengthen platform parity. Key work included PKCS#7 verification support with Ruby compatibility, Blowfish name support in EVP_CIPHER API, relaxed BER parsing rules, and Python 3.13 SSL/TLS patches with synchronized tests. Also integrated upstream Windows BIO test changes for binary/text mode handling and performed deprecation cleanup to streamline future maintenance.

November 2024

2 Commits • 1 Features

Nov 1, 2024

November 2024 monthly summary for aws/aws-lc: Delivered foundational PKCS7 data handling and secure encryption/decryption support. No major bug fixes reported for this repo in the month. The work strengthens security posture, improves interoperability for PKCS7 clients, and lays groundwork for RFC 3218 compliance and broader cryptographic tooling in the project.

October 2024

2 Commits • 1 Features

Oct 1, 2024

Month: 2024-10 | AWS/L2 contribution: aws/aws-lc What was delivered: - Implemented two internal BIO filters for PKCS7 processing to optimize data flow and cryptographic operations: BIO_f_cipher (encrypt/decrypt data when placed in front of another BIO) and BIO_f_md (efficient handling of message digests within PKCS7 processing). - Changes landed via two commits in aws/aws-lc: - 318c34c0920dfb11d2f7bc0c1a74e7ab9bd43403: Add PKCS7-internal BIO_f_cipher (#1836) - 11d7f4977946a8c9618da157eb5015c1175fc027: Add PKCS7-internal BIO_f_md (#1886) Why it matters: - Business value: Improves performance and security posture by streamlining PKCS7 data processing, enabling faster encryption/decryption and digest handling in common cryptographic workflows. - Technical impact: Adds extendable internal BIOs that pave the way for future PKCS7 optimizations, reducing overhead and improving maintainability of the crypto pipeline in aws/aws-lc. Skills and technologies demonstrated: - C programming and low-level BIO architecture within the OpenSSL-style BIO stack - PKCS7 processing pipeline knowledge and secure data flow optimization - Version control discipline with clear, reviewable commits and references

Activity

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Quality Metrics

Correctness92.6%
Maintainability87.2%
Architecture88.8%
Performance81.8%
AI Usage20.6%

Skills & Technologies

Programming Languages

CC++DiffGoJavaMarkdownPythonRustShellYAML

Technical Skills

API DevelopmentASN.1 ParsingBER EncodingBIOBIO filtersBuild SystemsBuild systems (CMake)CC DevelopmentC ProgrammingC programmingC++C++ DevelopmentC++ ProgrammingC++ programming

Repositories Contributed To

4 repos

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

aws/aws-lc

Oct 2024 Mar 2026
14 Months active

Languages Used

CC++PythonDiffShellGoYAMLMarkdown

Technical Skills

BIO filtersBuild systems (CMake)C/C++ developmentCryptographyLow-level programmingTesting

awslabs/aws-c-io

Oct 2025 Jan 2026
2 Months active

Languages Used

C

Technical Skills

CryptographySecurityTLSC programmingcryptographynetwork security

awslabs/aws-crt-java

Oct 2025 Oct 2025
1 Month active

Languages Used

Java

Technical Skills

CryptographySDK DevelopmentTLS

aws/s2n-tls

Feb 2026 Feb 2026
1 Month active

Languages Used

Rust

Technical Skills

Rustbenchmarkingcryptography