Crate poulpy_core

Expand description

Backend-agnostic Module-LWE-based homomorphic encryption primitives.

poulpy-core implements the cryptographic building blocks of a Module-LWE (MLWE) fully homomorphic encryption (FHE) scheme on top of the hardware-abstraction layer provided by poulpy_hal. The public operation traits live in api, while their blanket implementations on poulpy_hal::layouts::Module<BE> delegate to backend extension points in oep. This makes the crate portable across CPU, AVX, and future backends.

§Architecture

§Three-layer layout system

Every ciphertext and key type exists in three representations, defined in the layouts module:

Layer	Purpose	Generic params
Standard (`GLWE<D>`, `GGSW<D>`, …)	Serializable, platform-independent	`D: Data`
Compressed (`GLWECompressed<D>`, …)	Reduced storage via seed-based mask regeneration	`D: Data`
Prepared (`GLWEPrepared<D, B>`, …)	DFT-domain, optimised for fast polynomial arithmetic	`D: Data, B: Backend`

D: Data abstracts ownership: Vec<u8> (owned), &[u8] (borrowed), or &mut [u8] (mutable borrow).

§Scratch-space allocation

Operations never allocate on the heap internally. Instead, callers supply a poulpy_hal::layouts::ScratchArena borrow from which temporaries are arena-allocated via ScratchArenaTakeCore. Every operation that needs scratch space has a companion *_tmp_bytes method returning the required byte count.

§Parameter newtypes

Domain quantities are wrapped in u32-backed newtypes with saturating arithmetic: layouts::Degree, layouts::Base2K, layouts::TorusPrecision, layouts::Rank, layouts::Dnum, layouts::Dsize.

§Ciphertext types

layouts::LWE – Learning With Errors ciphertext (scalar ring element).
layouts::GLWE – Generalised LWE ciphertext (polynomial ring).
layouts::GGLWE – Gadget GLWE, a matrix of GLWE rows used for key-switching.
layouts::GGSW – Gadget GSW ciphertext, used as the left operand of external products.

§Module overview

Module	Responsibility
`api`	Safe, user-facing operation traits
`layouts`	Type definitions for all ciphertext, key, plaintext, and secret layouts
encryption	Secret-key, public-key, and compressed encryption
decryption	Decryption of GLWE, LWE, and tensor ciphertexts
operations	Ciphertext arithmetic (add, sub, rotate, shift, normalize, mul)
external_product	GGSW x GLWE external product (core HE multiplication)
keyswitching	Key-switching for GLWE, GGLWE, GGSW, and LWE
automorphism	Galois automorphisms on ciphertexts and keys
conversion	LWE / GLWE and GGLWE -> GGSW conversions
glwe_packer	On-the-fly GLWE packing with O(log N) memory
glwe_packing	HashMap-based GLWE slot packing
glwe_trace	GLWE trace (sum of automorphisms)
noise	Noise-variance estimation for parameter selection
dist	Secret-key distribution descriptors
scratch	Arena-style scratch allocation for ciphertext temporaries

Re-exports§

pub use api::*;
pub use default::encryption::*;
pub use default::operations::*;

Modules§

api: Safe, user-facing trait definitions for Module-LWE operations.
default
layouts: Ciphertext, key, plaintext, and secret-key layout types.
oep: Open extension points for poulpy-core.
test_suite

Macros§

core_backend_test_suite
impl_conversion_defaults_full: Implements [ConversionDefault] for Module<$be> by forwarding every method to the corresponding [conversion_defaults] free function.
impl_decryption_defaults_full: Implements [DecryptionDefault] for Module<$be> by forwarding every method to the corresponding [decryption_defaults] free function.
impl_encryption_defaults_full: Marker opt-in for [EncryptionDefault] on Module<$be>.
impl_gglwe_automorphism_defaults_full: Implements [GGLWEAutomorphismDefault] for Module<$be> by forwarding every method to the corresponding [gglwe_automorphism_defaults] free function.
impl_gglwe_external_product_defaults_full: Implements [GGLWEExternalProductDefault] for Module<$be> by forwarding every method to the corresponding [gglwe_external_product_defaults] free function.
impl_gglwe_keyswitch_defaults_full: Implements [GGLWEKeyswitchDefault] for Module<$be> by forwarding every method to the corresponding [gglwe_keyswitch_defaults] free function.
impl_ggsw_automorphism_defaults_full: Implements [GGSWAutomorphismDefault] for Module<$be> by forwarding every method to the corresponding [ggsw_automorphism_defaults] free function.
impl_ggsw_external_product_defaults_full: Implements [GGSWExternalProductDefault] for Module<$be> by forwarding every method to the corresponding [ggsw_external_product_defaults] free function.
impl_ggsw_keyswitch_defaults_full: Implements [GGSWKeyswitchDefault] for Module<$be> by forwarding every method to the corresponding [ggsw_keyswitch_defaults] free function.
impl_glwe_automorphism_defaults_full: Implements [GLWEAutomorphismDefault] for Module<$be> by forwarding every method to the corresponding [glwe_automorphism_defaults] free function.
impl_glwe_external_product_defaults_full: Implements [GLWEExternalProductDefault] for Module<$be> by forwarding every method to the corresponding [glwe_external_product_defaults] free function.
impl_glwe_keyswitch_defaults_full: Implements [GLWEKeyswitchDefault] for Module<$be> by forwarding every method to the corresponding [glwe_keyswitch_defaults] free function.
impl_glwe_packing_defaults_full: Implements [GLWEPackingDefault] for Module<$be> by forwarding every method to the corresponding [glwe_packing_defaults] free function.
impl_glwe_rotate_impl_from: Delegate the GLWERotateImpl family to another host backend through the module-owned transfer API.
impl_glwe_trace_defaults_full: Implements [GLWETraceDefault] for Module<$be> by forwarding every method to the corresponding [glwe_trace_defaults] free function.
impl_lwe_keyswitch_defaults_full: Implements [LWEKeyswitchDefault] for Module<$be> by forwarding every method to the corresponding [lwe_keyswitch_defaults] free function.

Enums§

Distribution: Describes the probability distribution used to sample secret-key coefficients.

Traits§

GetDistribution: Read-only access to the Distribution associated with a secret key.
GetDistributionMut: Mutable access to the Distribution associated with a secret key.
ScratchArenaTakeCore: Backend-native arena allocation for core ciphertext/key layouts.