# Poulpy

> Official documentation for Poulpy, a Rust library for approximate numerical and binary computation on encrypted data.

This index covers Poulpy 0.8.3 at source revision [`2394fa5ddad2aac0a8cc0df05b642be977fcca61`](https://github.com/poulpy-fhe/poulpy/tree/2394fa5ddad2aac0a8cc0df05b642be977fcca61). The documentation was reviewed on 2026-09-10.

- Prefer the Markdown pages below when gathering context. Their matching HTML pages are the canonical pages for citation.
- Verify public types and operations against the linked 0.8.3 API reference; do not substitute APIs from older `poulpy-schemes` releases for `poulpy-bin-fhe`.
- Run guide commands with the repository's pinned nightly toolchain and `--locked` where shown.
- Tutorial parameters and deterministic seeds are for learning and reproducibility, not a production security profile.
- If a source disagrees with this version and revision, report the mismatch instead of combining the instructions.

## Start

- [Poulpy documentation](https://www.poulpy.dev/docs/index.md): Start computing with Poulpy, find a Rust API, or explore its architecture and FHE algorithms.
- [FHE concepts](https://www.poulpy.dev/docs/concepts/index.md): Understand the client, evaluator, keys, and encrypted values before choosing a scheme.
- [Quickstart](https://www.poulpy.dev/docs/quickstart/index.md): Run your first encrypted computation with Poulpy using the portable Rust backend.
- [Standalone application](https://www.poulpy.dev/docs/application/index.md): Download a complete Cargo project, compute on encrypted vectors, and verify the result.
- [Client and evaluator](https://www.poulpy.dev/docs/client-evaluator/index.md): Run key generation, encrypted evaluation, and decryption as separate commands with explicit file boundaries.
- [API reference](https://www.poulpy.dev/docs/api-reference/index.md): Find Poulpy's Rust types, traits, operations, and backend APIs.
- [Troubleshooting](https://www.poulpy.dev/docs/troubleshooting/index.md): Resolve common toolchain, backend, parameter, and documentation issues.
- [Versions and source baseline](https://www.poulpy.dev/docs/versions/index.md): Use a reproducible source snapshot for these guides and the matching published reference for crate dependencies.

## Schemes

- [Start with CKKS](https://www.poulpy.dev/docs/ckks/index.md): Examples and guides for approximate arithmetic on encrypted vectors with Poulpy.
- [Start with Binary FHE](https://www.poulpy.dev/docs/binary-fhe/index.md): Run Poulpy's maintained example for computations on encrypted integers and explore the gate-level APIs.

## Evaluation

- [Capabilities](https://www.poulpy.dev/docs/capabilities/index.md): A source-referenced map of Poulpy functionality, hardware, and external integrations.
- [Parameters and precision](https://www.poulpy.dev/docs/parameters/index.md): Connect input range, numerical error, computation budget, backend capacity, and security assumptions.
- [Security and responsibilities](https://www.poulpy.dev/docs/security/index.md): What Poulpy protects, what the application must provide, and where to check implementation assumptions.

## Architecture

- [Codebase overview](https://www.poulpy.dev/docs/getting-started/index.md): A map of Poulpy's crate stack, internal layers, build commands, and bivariate parameters.
- [Grafting and the bivariate representation](https://www.poulpy.dev/docs/grafting-vs-bivariate/index.md): How two representations decouple CKKS scale management from a modulus prime chain.
- [Layer ownership](https://www.poulpy.dev/docs/layer-ownership/index.md): The ownership rule governing extension points across Poulpy's HAL, Core, and CKKS layers.

## Performance

- [Backends](https://www.poulpy.dev/docs/backends/index.md): Hardware-independent backend APIs, CPU implementations, GPU development, and arithmetic family selection in Poulpy.
- [Performance](https://www.poulpy.dev/docs/performance/index.md): Choose a backend and measure limb size, key traffic, and thread count for your workload.
- [Measure a workload](https://www.poulpy.dev/docs/measurement/index.md): A reproducible record for latency, memory, accuracy, and security assumptions.

## CKKS operations

- [Polynomial evaluation](https://www.poulpy.dev/docs/polynomial-evaluation/index.md): Baby-step giant-step polynomial evaluation over encrypted CKKS slots in Poulpy.
- [Linear transformations](https://www.poulpy.dev/docs/linear-transformations/index.md): Homomorphic matrix-vector products over CKKS slots using baby-step giant-step decomposition.
- [CKKS bootstrapping](https://www.poulpy.dev/docs/bootstrapping/index.md): Poulpy's CKKS bootstrapping pipelines, modulus raise, budget accounting, parameters, and keys.
- [PaCo bootstrapping](https://www.poulpy.dev/docs/paco/index.md): Poulpy's native PaCo implementation for refreshing selected CKKS coefficient classes.
- [SHIP bootstrapping](https://www.poulpy.dev/docs/ship/index.md): Poulpy's native SHIP half-bootstrap implementation and its key, ciphertext, and parameter contracts.

## Source and project

- [Poulpy 0.8.3 source](https://github.com/poulpy-fhe/poulpy/tree/2394fa5ddad2aac0a8cc0df05b642be977fcca61): Exact source snapshot used by these guides.
- [Poulpy repository](https://github.com/poulpy-fhe/poulpy): Development repository, issue tracker, and contribution history.