Struct PSFGPV 

pub struct PSFGPV {
    pub gp: GadgetParameters,
    pub s: Q,
}

A lattice-based implementation of a PSF according to [1] using G-Trapdoors where D_n = {e ∈ Z^m | |e| <= s sqrt(m)} and R_n = Z_q^n.

Attributes

• gp: Describes the gadget parameters with which the G-Trapdoor is generated
• s: The Gaussian parameter with which is sampled

Examples

use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};

let (a, td) = psf.trap_gen();
let domain_sample = psf.samp_d();
let range_fa = psf.f_a(&a, &domain_sample);
let preimage = psf.samp_p(&a, &td, &range_fa);

assert!(psf.check_domain(&preimage));

Fields

gp: GadgetParameters

s: Q

Trait Implementations

impl<'de> Deserialize<'de> for PSFGPV

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PSF for PSFGPV

fn trap_gen(&self) -> (MatZq, (MatZ, MatQ))

Computes a G-Trapdoor according to the GadgetParameters defined in the struct. It returns a matrix A together with a short base and its GSO.

Examples

use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};

let (a, (sh_b, sh_b_gso)) = psf.trap_gen();

fn samp_d(&self) -> MatZ

Samples in the domain using SampleD with the standard basis and center 0.

Examples

use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};
let (a, td) = psf.trap_gen();

let domain_sample = psf.samp_d();

fn samp_p( &self, a: &MatZq, (short_base, short_base_gso): &(MatZ, MatQ), u: &MatZq, ) -> MatZ

Samples an e in the domain using SampleD with a short basis that is generated from the G-Trapdoor from the conditioned conditioned discrete Gaussian with f_a(a,e) = u for a provided syndrome u.

Note: the provided parameters a,r,u must fit together, otherwise unexpected behavior such as panics may occur.

Parameters:

• a: The parity-check matrix
• short_base: The short base for Λ^⟂(A)
• short_base_gso: The precomputed GSO of the short_base
• u: The syndrome from the range

Returns a sample e from the domain on the conditioned discrete Gaussian distribution f_a(a,e) = u.

Examples

use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};
let (a, td) = psf.trap_gen();
let domain_sample = psf.samp_d();
let range_fa = psf.f_a(&a, &domain_sample);

let preimage = psf.samp_p(&a, &td, &range_fa);
assert_eq!(range_fa, psf.f_a(&a, &preimage))

fn f_a(&self, a: &MatZq, sigma: &MatZ) -> MatZq

Implements the efficiently computable function f_a which here corresponds to a*sigma. The sigma must be from the domain, i.e. D_n.

Parameters:

• a: The parity-check matrix of dimensions n x m
• sigma: A column vector of length m

Returns a*sigma

Examples

use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};
let (a, td) = psf.trap_gen();
let domain_sample = psf.samp_d();
let range_fa = psf.f_a(&a, &domain_sample);

Panics …

• if sigma is not in the domain.

fn check_domain(&self, sigma: &MatZ) -> bool

Checks whether a value sigma is in D_n = {e ∈ Z^m | |e| <= s sqrt(m)}.

Parameters:

• sigma: The value for which is checked, if it is in the domain

Returns true, if sigma is in D_n.

Examples

use qfall_tools::primitive::psf::PSF;
use qfall_tools::primitive::psf::PSFGPV;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParameters;
use qfall_math::rational::Q;

let psf = PSFGPV {
    gp: GadgetParameters::init_default(8, 64),
    s: Q::from(12),
};
let (a, td) = psf.trap_gen();

let vector = psf.samp_d();

assert!(psf.check_domain(&vector));

type A = MatZq

type Trapdoor = (MatZ, MatQ)

type Domain = MatZ

type Range = MatZq

impl Serialize for PSFGPV

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.