LatticeHelper

Idea to create this library came up from seeing concrete similarities between different custom PQ lattice-based protocols (two-party signature and e-vote casting).

The purpose is to have a common set of full-fledged functions available in multiple components. This will allow for a more consistent and efficient development of PQ components.

Under the hood, it is utilizing LattiGo library for its ring capabilities (and more importantly NTT and INTT functions for fast polynomial multiplication).

Features

• Polynomial arithmetic in two different rings:
  • ring R over Z[X]/(X^d + 1)
    • coefficients are all natural numbers, poly is modulo X^d + 1
    • in this library, naming is regular poly...
  • ring Rq over Z_q[X]/(X^d + 1)
    • coefficients are in range from 0 to q-1, poly is modulo X^d + 1
    • in this library, naming is polyQ...
• Vector and matrix arithmetic in both rings.
• some util functions like Power2Round, checking bounds, norms, etc.

Install

Use go get github.com/isri-pqc/latticehelper to download and use in your Go module.

Initialization

latticehelper.InitSingle() or latticehelper.InitMultiple() MUST be called at least once before using anything related to polyQ. Arguments for latticehelper.InitSingle() are maximum degree of polynomial d + single modulus q.

InitMultiple can prepare underlying parameters between multiple rings Rq, but has not been tested that much yet. Second argument must be a slice of moduli [q1, q2, q3,...].

Concurrency

If not stated otherwise, all functions should be thread safe and do not require any locks.

Only exceptions to that rule are functions NewRandomPolyQ{matrix|vector|""}, which require a thread-unique sampler. If these functions are used concurrently (i.e. called multiple times at the same time), create new sampler in each thread by latticehelper.NewSampler for them.

Acknowledgements

Developed under CHESS project.

Funded by the European Union under Grant Agreement No. 101087529. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Research Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.