About FHElium
FHElium is an open-source, research-oriented framework for fully homomorphic encryption (FHE), with a current implementation focused on CKKS. It connects program representation, cryptographic state, execution, runtime resource management, distributed systems, and hardware acceleration so that they can be studied independently or together.
Why FHElium exists
FHE inference is supported by an increasingly capable full stack. Compiler frontends and intermediate representations translate application operators into legal encrypted programs. Algorithm and compiler research improves packing, approximation, scale management, and circuit planning. Software backends and optimized kernels accelerate the resulting primitives, while runtimes, distributed systems, and specialized hardware provide additional execution capacity. These advances are complementary and together form the modern FHE inference ecosystem.
The resulting system, however, is not the sum of independent local optima. Program representation and packing determine rotations, keys, and data layout. CKKS state determines numerical behavior, storage volume, and operation cost. Execution order changes temporary memory, data movement, and communication. Workload and runtime conditions change which decisions are effective, while hardware characteristics feed back into algorithm, compiler, and scheduling choices. Optimizing only one layer, or isolating every layer behind an opaque interface, can miss opportunities that appear only when these effects are considered together.
FHElium provides a modular research framework in which cross-layer designs can be expressed, transformed, executed, measured, and validated. Users choose their level of control, specialized components connect through replaceable interfaces, and runtime evidence can guide optimization while remaining inspectable.
What characterizes FHElium
1. Full-stack by design
FHElium connects encrypted programming, compilation, execution, runtime systems, and hardware optimization in one research stack. Immediate execution with Eager and program-based execution with Compile are both first-class ways to work across this stack.
2. Choices remain visible
FHElium exposes the decisions that shape an encrypted computation. Researchers can change representations, transformations, execution strategies, and runtime policies at the layer that owns them.
3. Evidence across layers
FHElium evaluates numerical correctness alongside latency, memory, communication, and hardware behavior. A local optimization can be traced to its effect on the complete workload.
Work in progress
Multiple execution backends
FHElium develops execution backends optimized for different microarchitectures under shared value and operator semantics. To expand this research, we welcome donated hardware or sustained remote access to representative datacenter accelerators; interested organizations are invited to contact us.
Compiler and ecosystem interoperability
FHElium's versioned CKKS operation vocabulary and extensible representation support interoperability with tensor frontends, external compilers, program-analysis tools, transformation pipelines, code generators, and deployment systems. Focused adapters extend this model to runtimes, persistence, profiling, and benchmarking while each subsystem retains its own policy.
Agentic AI ready
FHElium's CKKS state, structured requirements, diagnostics, and reproducible evidence are intended to give agentic systems feedback they can act on. The goal is for an agent to translate a cleartext program into an encrypted program or tune an encrypted workload's performance while keeping each transformation, assumption, and validation result observable and debuggable.