Struct PSFGPVRing 

pub struct PSFGPVRing {
    pub gp: GadgetParametersRing,
    pub s: Q,
    pub s_td: Q,
}

A lattice-based implementation of a PSF according to [1] and [2] using G-Trapdoors where D_n = {e ∈ R^m | |ι(e)| <= s sqrt(m*n) } and R_n = R_q.

Attributes

• gp: Describes the gadget parameters with which the G-Trapdoor is generated
• s: The Gaussian parameter with which elements from the domain are sampled
• s:td: The Gaussian parameter with which the trapdoor is sampled

Examples

use qfall_tools::primitive::psf::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};

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

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

Fields

gp: GadgetParametersRing

s: Q

s_td: Q

Trait Implementations

impl<'de> Deserialize<'de> for PSFGPVRing

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PSF for PSFGPVRing

fn trap_gen(&self) -> (MatPolynomialRingZq, (MatPolyOverZ, MatPolyOverZ))

Computes a G-Trapdoor according to the GadgetParametersRing.

Examples

use qfall_tools::primitive::psf::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};
let (a, (r, e)) = psf.trap_gen();

fn samp_d(&self) -> MatPolyOverZ

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

Examples

use qfall_tools::primitive::psf::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};
let (a, (r, e)) = psf.trap_gen();

let domain_sample = psf.samp_d();

fn samp_p( &self, a: &MatPolynomialRingZq, (r, e): &(MatPolyOverZ, MatPolyOverZ), u: &MatPolynomialRingZq, ) -> MatPolyOverZ

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

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

Parameters:

• a: The parity-check matrix
• r: Together with e builds a G-Trapdoor for a
• e: Together with r builds a G-Trapdoor for a
• 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::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};
let (a, (r, e)) = psf.trap_gen();

let domain_sample = psf.samp_d();
let range_fa = psf.f_a(&a, &domain_sample);

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

fn f_a( &self, a: &MatPolynomialRingZq, sigma: &MatPolyOverZ, ) -> MatPolynomialRingZq

Implements the efficiently computable function f_a which here corresponds to a*sigma.

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::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};
let (a, (r, e)) = 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: &MatPolyOverZ) -> bool

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

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::PSFGPVRing;
use qfall_tools::sample::g_trapdoor::gadget_parameters::GadgetParametersRing;
use qfall_math::rational::Q;
use qfall_tools::primitive::psf::PSF;

let psf = PSFGPVRing {
    gp: GadgetParametersRing::init_default(8, 512),
    s: Q::from(100),
    s_td: Q::from(1.005_f64),
};
let (a, (r, e)) = psf.trap_gen();

let vector = psf.samp_d();

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

type A = MatPolynomialRingZq

type Trapdoor = (MatPolyOverZ, MatPolyOverZ)

type Domain = MatPolyOverZ

type Range = MatPolynomialRingZq

impl Serialize for PSFGPVRing

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

where __S: Serializer,

Serialize this value into the given Serde serializer.