NTPIR

This repository contains the Rust implementation of NTPIR, a silent-preprocessing PIR scheme that uses NTRU ciphertexts as the second-layer intermediate ciphertexts in the Double PIR paradigm.

Implementation

The implementation includes the following components:

• LWE-to-RLWE packing using InspiRING and RLWE-to-NTRU conversion
• encrypted unit queries and Split-Point Picking
• the plaintext z-tree and PackRLWEs
• base-31 digit decomposition and response extraction
• FFT-based polynomial arithmetic and approximate gadget decomposition

Requirements

• the Rust nightly toolchain specified in rust-toolchain.toml
• Linux on an x86-64 processor with AVX-512 support

Build

Build the library and the included executables from the repository root:

RUSTFLAGS="-C target-cpu=native" cargo build --release --bins

Correctness Verification

Run the complete correctness verification with:

./scripts/verify_correctness.sh

The script verifies NTRU key generation, encryption and decryption, key switching, automorphisms, encrypted unit queries, PackRLWEs, Split-Point Picking, digit decomposition, and response extraction. It also checks the complete Stage 2--4 computation for all supported split configurations.

An optional argument specifies the number of repeated end-to-end trials. For example, the following command runs one repeated trial after checking all supported configurations:

./scripts/verify_correctness.sh 1

Repository Structure

• src/fft.rs implements negacyclic polynomial multiplication.
• src/pir_fft/ contains the protocol implementation.
• src/bin/verify_*.rs contains the correctness verification programs.
• scripts/verify_correctness.sh runs the complete verification procedure.

License

Apache-2.0