
Andrei Stoian developed and optimized GPU-accelerated cryptographic operations for the zama-ai/tfhe-rs repository, focusing on scalable machine learning workloads. He engineered CUDA-based keyswitch packing and polynomial multiplication, introducing runtime device checks for dynamic GPU usage and robust error handling. Andrei enhanced multi-GPU support, deterministic testing, and benchmarking workflows, while improving CI/CD pipelines with dynamic GCC management and memory safety tooling. His work included refactoring CUDA kernels, streamlining build systems, and expanding technical documentation. Leveraging C++, CUDA, and Rust, Andrei delivered maintainable, high-performance code that improved reliability, testability, and developer productivity across GPU computing and cryptographic software infrastructure.

2025-10 — Focused on stabilizing the GPU coprocessor path in zama-ai/tfhe-rs. Delivered a robust fix to the GPU coprocessor installation workflow that corrects npm dependency installation and ensures host contracts deploy and compile reliably, stabilizing GPU benchmarks. This improves reliability of GPU-enabled crypto workloads and enhances benchmarking repeatability, enabling faster, more accurate performance assessments and customer-facing reporting.
2025-10 — Focused on stabilizing the GPU coprocessor path in zama-ai/tfhe-rs. Delivered a robust fix to the GPU coprocessor installation workflow that corrects npm dependency installation and ensures host contracts deploy and compile reliably, stabilizing GPU benchmarks. This improves reliability of GPU-enabled crypto workloads and enhances benchmarking repeatability, enabling faster, more accurate performance assessments and customer-facing reporting.
September 2025 — zama-ai/tfhe-rs: Multi-GPU backend and testing improvements delivering reliability, performance visibility, and deterministic validation across GPUs. Key features delivered - Multi-GPU Backend and Benchmarking Enhancements: Consolidated CUDA stream management, improved cross-GPU synchronization, enhanced benchmarking workflow for manual-dispatch and instance selection, and added a dedicated fake multi-GPU debug mode to accelerate development and validation across GPUs. Commit highlights include: 1dcc3c8c898cfebe243f82a9bbe458e9990b96ce, 87c0d646a4bfadcf0bf3b39f6ba7fb323e27cfcf, 30938eec74408b037aae5ffc2af352471d7658fa, 0604d237ebbe42675519071733c7170e14556292. - Deterministic GPU Testing and Reliability Improvements: Introduced seeded RNG for GPU device selection and operation sequencing to ensure deterministic GPU tests, updating executor types and setup to support reproducible test runs. Commit: 73de886c074959b45e049a59bbf0944dd46002f4. Major bugs fixed - Fixed issues related to coprocessor benchmarking under GPU workloads, contributing to more stable and repeatable benchmark results. (Evidence: commit fix(gpu): coprocessor bench) Overall impact and accomplishments - Increased reliability and predictability of multi-GPU tests and benchmarks, enabling faster performance tuning, more confident release planning, and reduced debugging time. Supports scalable validation across GPUs and clearer benchmarking signals for optimization. Technologies and skills demonstrated - GPU programming patterns: CUDA stream consolidation, multi-GPU synchronization, and fake multi-GPU debugging workflows - Benchmark design and reproducibility: seeded RNG for deterministic tests and updated executors for stable runs - Cross-GPU validation tooling and development enablement
September 2025 — zama-ai/tfhe-rs: Multi-GPU backend and testing improvements delivering reliability, performance visibility, and deterministic validation across GPUs. Key features delivered - Multi-GPU Backend and Benchmarking Enhancements: Consolidated CUDA stream management, improved cross-GPU synchronization, enhanced benchmarking workflow for manual-dispatch and instance selection, and added a dedicated fake multi-GPU debug mode to accelerate development and validation across GPUs. Commit highlights include: 1dcc3c8c898cfebe243f82a9bbe458e9990b96ce, 87c0d646a4bfadcf0bf3b39f6ba7fb323e27cfcf, 30938eec74408b037aae5ffc2af352471d7658fa, 0604d237ebbe42675519071733c7170e14556292. - Deterministic GPU Testing and Reliability Improvements: Introduced seeded RNG for GPU device selection and operation sequencing to ensure deterministic GPU tests, updating executor types and setup to support reproducible test runs. Commit: 73de886c074959b45e049a59bbf0944dd46002f4. Major bugs fixed - Fixed issues related to coprocessor benchmarking under GPU workloads, contributing to more stable and repeatable benchmark results. (Evidence: commit fix(gpu): coprocessor bench) Overall impact and accomplishments - Increased reliability and predictability of multi-GPU tests and benchmarks, enabling faster performance tuning, more confident release planning, and reduced debugging time. Supports scalable validation across GPUs and clearer benchmarking signals for optimization. Technologies and skills demonstrated - GPU programming patterns: CUDA stream consolidation, multi-GPU synchronization, and fake multi-GPU debugging workflows - Benchmark design and reproducibility: seeded RNG for deterministic tests and updated executors for stable runs - Cross-GPU validation tooling and development enablement
August 2025: Focused on stability, correctness, and developer productivity in the zama-ai/tfhe-rs repository. Delivered GPU backend error handling enhancements, CI/build workflow improvements, and performed minor codebase polish. These changes improve runtime reliability, reduce CI build times, and enable better profiling and debugging for CUDA paths.
August 2025: Focused on stability, correctness, and developer productivity in the zama-ai/tfhe-rs repository. Delivered GPU backend error handling enhancements, CI/build workflow improvements, and performed minor codebase polish. These changes improve runtime reliability, reduce CI build times, and enable better profiling and debugging for CUDA paths.
In July 2025, GPU-focused CI enhancements and CUDA backend hardening were delivered for the tfhe-rs project, driving faster GPU benchmarking, improved issue detection, and cleaner build signals across the GPU software stack.
In July 2025, GPU-focused CI enhancements and CUDA backend hardening were delivered for the tfhe-rs project, driving faster GPU benchmarking, improved issue detection, and cleaner build signals across the GPU software stack.
June 2025 monthly summary for zama-ai/tfhe-rs. Focused on strengthening GPU-related build performance, test reliability, CI efficiency, and developer documentation. Key initiatives and outcomes below.
June 2025 monthly summary for zama-ai/tfhe-rs. Focused on strengthening GPU-related build performance, test reliability, CI efficiency, and developer documentation. Key initiatives and outcomes below.
April 2025 monthly summary for zama-ai/concrete-ml: Delivered a targeted dependency upgrade of Concrete-ML Extensions to 0.1.9, aligning licenses and lockfiles to improve consistency, stability, and access to library bug fixes and improvements. This work reduces drift between components and supports smoother downstream integration and CI.
April 2025 monthly summary for zama-ai/concrete-ml: Delivered a targeted dependency upgrade of Concrete-ML Extensions to 0.1.9, aligning licenses and lockfiles to improve consistency, stability, and access to library bug fixes and improvements. This work reduces drift between components and supports smoother downstream integration and CI.
January 2025 monthly summary focused on enhancing runtime configurability and maintainability through flexible parameter management and clear documentation. Delivered a new dictionary-based parameter loading path for TFHE parameters and added comprehensive provenance documentation for a CUDA GEMM kernel, improving traceability and onboarding for future work. No critical bugs reported or fixed this month; primary value came from more robust configuration, test coverage, and documentation that supports lean deployments and easier cross-repo collaboration.
January 2025 monthly summary focused on enhancing runtime configurability and maintainability through flexible parameter management and clear documentation. Delivered a new dictionary-based parameter loading path for TFHE parameters and added comprehensive provenance documentation for a CUDA GEMM kernel, improving traceability and onboarding for future work. No critical bugs reported or fixed this month; primary value came from more robust configuration, test coverage, and documentation that supports lean deployments and easier cross-repo collaboration.
Month: 2024-12 — Focused on delivering performance improvements in tfhe-rs by enabling GPU-accelerated packing of keyswitch data. The work involved refactoring CUDA kernels, removing an unnecessary fast-path check, and using optimized host routines to reduce latency and memory overhead. Delivered as a single feature with clean, reviewable changes that enhance cryptographic throughput on GPU-powered workloads.
Month: 2024-12 — Focused on delivering performance improvements in tfhe-rs by enabling GPU-accelerated packing of keyswitch data. The work involved refactoring CUDA kernels, removing an unnecessary fast-path check, and using optimized host routines to reduce latency and memory overhead. Delivered as a single feature with clean, reviewable changes that enhance cryptographic throughput on GPU-powered workloads.
November 2024: Delivered GPU-accelerated cryptographic operations in tfhe-rs with runtime CUDA availability checks, enabling dynamic GPU usage for ML workloads. Implementations include a fast-path keyswitch packing optimized for ML, circulant-matrix based GPU polynomial multiplication, and a runtime CUDA device availability check to gracefully fallback when GPUs are unavailable. These changes unlock substantial performance improvements in ML inference workloads and improve scalability across heterogeneous hardware.
November 2024: Delivered GPU-accelerated cryptographic operations in tfhe-rs with runtime CUDA availability checks, enabling dynamic GPU usage for ML workloads. Implementations include a fast-path keyswitch packing optimized for ML, circulant-matrix based GPU polynomial multiplication, and a runtime CUDA device availability check to gracefully fallback when GPUs are unavailable. These changes unlock substantial performance improvements in ML inference workloads and improve scalability across heterogeneous hardware.
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