ring

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Published: Nov 28, 2023 License: Apache-2.0 Imports: 15 Imported by: 37

README

References

  1. Faster arithmetic for number-theoretic transforms (https://arxiv.org/abs/1205.2926)
  2. Speeding up the Number Theoretic Transform for Faster Ideal Lattice-Based Cryptography (https://eprint.iacr.org/2016/504)
  3. Gaussian sampling in lattice-based cryptography (https://tel.archives-ouvertes.fr/tel-01245066v2)
  4. Post-quantum key exchange - a new hope (https://eprint.iacr.org/2015/1092)

Documentation

Overview

Package ring implements RNS-accelerated modular arithmetic operations for polynomials, including: RNS basis extension; RNS rescaling; number theoretic transform (NTT); uniform, Gaussian and ternary sampling.

Index

Constants

View Source
const (
	// GaloisGen is an integer of order N/2 modulo M that spans Z_M with the integer -1.
	// The j-th ring automorphism takes the root zeta to zeta^(5j).
	GaloisGen uint64 = 5

	// MinimumRingDegreeForLoopUnrolledOperations is the minimum ring degree required to
	// safely perform loop-unrolled operations
	MinimumRingDegreeForLoopUnrolledOperations = 8
)
View Source
const (
	Standard           = Type(0) // Z[X]/(X^N + 1) (Default)
	ConjugateInvariant = Type(1) // Z[X+X^-1]/(X^2N + 1)
)

RingStandard and RingConjugateInvariant are two types of Rings.

View Source
const (
	// MinimumRingDegreeForLoopUnrolledNTT is the minimum ring degree
	// necessary for memory safe loop unrolling
	MinimumRingDegreeForLoopUnrolledNTT = 16
)

Variables

View Source
var Pi60 = []uint64{0x1ffffffff6c80001, 0x1ffffffff6140001, 0x1ffffffff5f40001, 0x1ffffffff5700001,
	0x1ffffffff4bc0001, 0x1ffffffff4380001, 0x1ffffffff3240001, 0x1ffffffff2dc0001,
	0x1ffffffff1a40001, 0x1ffffffff11c0001, 0x1ffffffff0fc0001, 0x1ffffffff0d80001,
	0x1ffffffff0c80001, 0x1ffffffff08c0001, 0x1fffffffefd00001, 0x1fffffffef9c0001,
	0x1fffffffef600001, 0x1fffffffeef40001, 0x1fffffffeed40001, 0x1fffffffeed00001,
	0x1fffffffeebc0001, 0x1fffffffed540001, 0x1fffffffed440001, 0x1fffffffed2c0001,
	0x1fffffffed200001, 0x1fffffffec940001, 0x1fffffffec6c0001, 0x1fffffffebe80001,
	0x1fffffffebac0001, 0x1fffffffeba40001, 0x1fffffffeb4c0001, 0x1fffffffeb280001}

Pi60 are the next [32:64] 61-bit close to 2^{62} NTT-friendly primes for N up to 2^{17}

View Source
var Qi60 = []uint64{0x1fffffffffe00001, 0x1fffffffffc80001, 0x1fffffffffb40001, 0x1fffffffff500001,
	0x1fffffffff380001, 0x1fffffffff000001, 0x1ffffffffef00001, 0x1ffffffffee80001,
	0x1ffffffffeb40001, 0x1ffffffffe780001, 0x1ffffffffe600001, 0x1ffffffffe4c0001,
	0x1ffffffffdf40001, 0x1ffffffffdac0001, 0x1ffffffffda40001, 0x1ffffffffc680001,
	0x1ffffffffc000001, 0x1ffffffffb880001, 0x1ffffffffb7c0001, 0x1ffffffffb300001,
	0x1ffffffffb1c0001, 0x1ffffffffadc0001, 0x1ffffffffa400001, 0x1ffffffffa140001,
	0x1ffffffff9d80001, 0x1ffffffff9140001, 0x1ffffffff8ac0001, 0x1ffffffff8a80001,
	0x1ffffffff81c0001, 0x1ffffffff7800001, 0x1ffffffff7680001, 0x1ffffffff7080001}

Qi60 are the first [0:32] 61-bit close to 2^{62} NTT-friendly primes for N up to 2^{17}

Functions

func AutomorphismNTTIndex

func AutomorphismNTTIndex(N int, NthRoot, GalEl uint64) (index []uint64, err error)

AutomorphismNTTIndex computes the look-up table for the automorphism X^{i} -> X^{i*k mod NthRoot}.

func BRed

func BRed(x, y, q uint64, u []uint64) (r uint64)

BRed computes x*y mod q.

func BRedAdd

func BRedAdd(a, q uint64, u []uint64) (r uint64)

BRedAdd computes a mod q.

func BRedAddLazy

func BRedAddLazy(x, q uint64, u []uint64) uint64

BRedAddLazy computes a mod q in constant time. The result is between 0 and 2*q-1.

func BRedConstant

func BRedConstant(q uint64) (constant []uint64)

BRedConstant computes the constant for the BRed algorithm. Returns ((2^128)/q)/(2^64) and (2^128)/q mod 2^64.

func BRedLazy

func BRedLazy(x, y, q uint64, u []uint64) (r uint64)

BRedLazy computes x*y mod q in constant time. The result is between 0 and 2*q-1.

func CRed

func CRed(a, q uint64) uint64

CRed reduce returns a mod q where a is between 0 and 2*q-1.

func CheckFactors

func CheckFactors(m uint64, factors []uint64) (err error)

CheckFactors checks that the given list of factors contains all the unique primes of m.

func CheckPrimitiveRoot

func CheckPrimitiveRoot(g, q uint64, factors []uint64) (err error)

CheckPrimitiveRoot checks that g is a valid primitive root mod q, given the factors of q-1.

func EvalPolyModP

func EvalPolyModP(x uint64, poly []uint64, p uint64) (y uint64)

EvalPolyModP evaluates y = sum poly[i] * x^{i} mod p.

func IMForm

func IMForm(a, q, qInv uint64) (r uint64)

IMForm switches a from the Montgomery domain back to the standard domain by computing a*(1/2^64) mod q.

func IMFormLazy

func IMFormLazy(a, q, qInv uint64) (r uint64)

IMFormLazy switches a from the Montgomery domain back to the standard domain by computing a*(1/2^64) mod q in constant time. The result is between 0 and 2*q-1.

func INTTConjugateInvariant

func INTTConjugateInvariant(p1, p2 []uint64, N int, NInv, Q, MRedConstant uint64, roots []uint64)

INTTConjugateInvariant evaluates p2 = INTT(p1) in the closed sub-ring Z[X + X^-1]/(X^2N +1) of Z[X]/(X^2N+1).

func INTTConjugateInvariantLazy

func INTTConjugateInvariantLazy(p1, p2 []uint64, N int, NInv, Q, MRedConstant uint64, roots []uint64)

INTTConjugateInvariantLazy evaluates p2 = INTT(p1) in the closed sub-ring Z[X + X^-1]/(X^2N +1) of Z[X]/(X^2N+1) with p2 in the range [0, 2*modulus-1].

func INTTStandard

func INTTStandard(p1, p2 []uint64, N int, NInv, Q, MRedConstant uint64, roots []uint64)

INTTStandard evalues p2 = INTTStandard(p1) in the given SubRing.

func INTTStandardLazy

func INTTStandardLazy(p1, p2 []uint64, N int, NInv, Q, MRedConstant uint64, roots []uint64)

INTTStandardLazy evalues p2 = INTT(p1) in the given SubRing with p2 in [0, 2*modulus-1].

func IsPrime

func IsPrime(x uint64) bool

IsPrime applies the Baillie-PSW, which is 100% accurate for numbers bellow 2^64.

func MForm

func MForm(a, q uint64, u []uint64) (r uint64)

MForm switches a to the Montgomery domain by computing a*2^64 mod q.

func MFormLazy

func MFormLazy(a, q uint64, u []uint64) (r uint64)

MFormLazy switches a to the Montgomery domain by computing a*2^64 mod q in constant time. The result is between 0 and 2*q-1.

func MRed

func MRed(x, y, q, qInv uint64) (r uint64)

MRed computes x * y * (1/2^64) mod q.

func MRedConstant

func MRedConstant(q uint64) (qInv uint64)

MRedConstant computes the constant qInv = (q^-1) mod 2^64 required for MRed.

func MRedLazy

func MRedLazy(x, y, q, qInv uint64) (r uint64)

MRedLazy computes x * y * (1/2^64) mod q in constant time. The result is between 0 and 2*q-1.

func MapSmallDimensionToLargerDimensionNTT

func MapSmallDimensionToLargerDimensionNTT(polSmall, polLarge Poly)

MapSmallDimensionToLargerDimensionNTT maps Y = X^{N/n} -> X directly in the NTT domain

func MaskVec

func MaskVec(p1 []uint64, w int, mask uint64, p2 []uint64)

MaskVec evaluates p2 = vec(p1>>w) & mask Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func Min

func Min(x, y int) int

Min returns the minimum between to int

func ModExp

func ModExp(x, e, p uint64) (result uint64)

ModExp performs the modular exponentiation x^e mod p, x and p are required to be at most 64 bits to avoid an overflow.

func ModExpPow2

func ModExpPow2(x, e, p uint64) (result uint64)

ModExpPow2 performs the modular exponentiation x^e mod p, where p is a power of two, x and p are required to be at most 64 bits to avoid an overflow.

func ModUpExact

func ModUpExact(p1, p2 [][]uint64, ringQ, ringP *Ring, MUC ModUpConstants)

ModUpExact takes p1 mod Q and switches its basis to P, returning the result on p2. Caution: values are not centered and returned values are in [0, 2P-1].

func ModexpMontgomery

func ModexpMontgomery(x uint64, e int, q, qInv uint64, bredconstant []uint64) (result uint64)

ModexpMontgomery performs the modular exponentiation x^e mod p, where x is in Montgomery form, and returns x^e in Montgomery form.

func NTTConjugateInvariant

func NTTConjugateInvariant(p1, p2 []uint64, N int, Q, MRedConstant uint64, BRedConstant, roots []uint64)

NTTConjugateInvariant evaluates p2 = NTT(p1) in the sub-ring Z[X + X^-1]/(X^2N +1) of Z[X]/(X^2N+1).

func NTTConjugateInvariantLazy

func NTTConjugateInvariantLazy(p1, p2 []uint64, N int, Q, MRedConstant uint64, roots []uint64)

NTTConjugateInvariantLazy evaluates p2 = NTT(p1) in the sub-ring Z[X + X^-1]/(X^2N +1) of Z[X]/(X^2N+1) with p2 in the range [0, 2*modulus-1].

func NTTStandard

func NTTStandard(p1, p2 []uint64, N int, Q, MRedConstant uint64, BRedConstant, roots []uint64)

NTTStandard computes the NTTStandard in the given SubRing.

func NTTStandardLazy

func NTTStandardLazy(p1, p2 []uint64, N int, Q, MRedConstant uint64, roots []uint64)

NTTStandardLazy computes the NTTStandard in the given SubRing with p2 in [0, 2*modulus-1].

func PrimitiveRoot

func PrimitiveRoot(q uint64, factors []uint64) (uint64, []uint64, error)

PrimitiveRoot computes the smallest primitive root of the given prime q The unique factors of q-1 can be given to speed up the search for the root.

func RandUniform

func RandUniform(prng sampling.PRNG, v uint64, mask uint64) (randomInt uint64)

RandUniform samples a uniform randomInt variable in the range [0, mask] until randomInt is in the range [0, v-1]. mask needs to be of the form 2^n -1.

func ZeroVec

func ZeroVec(p1 []uint64)

ZeroVec sets all values of p1 to zero. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

Types

type BasisExtender

type BasisExtender struct {
	// contains filtered or unexported fields
}

BasisExtender stores the necessary parameters for RNS basis extension. The used algorithm is from https://eprint.iacr.org/2018/117.pdf.

func NewBasisExtender

func NewBasisExtender(ringQ, ringP *Ring) (be *BasisExtender)

NewBasisExtender creates a new BasisExtender, enabling RNS basis extension from Q to P and P to Q.

func (*BasisExtender) ModDownQPtoP

func (be *BasisExtender) ModDownQPtoP(levelQ, levelP int, p1Q, p1P, p2P Poly)

ModDownQPtoP reduces the basis of a polynomial. Given a polynomial with coefficients in basis {Q0,Q1....QlevelQ} and {P0,P1...PlevelP}, it reduces its basis from {Q0,Q1....QlevelQ} and {P0,P1...PlevelP} to {P0,P1...PlevelP} and does a floored integer division of the result by Q.

func (*BasisExtender) ModDownQPtoQ

func (be *BasisExtender) ModDownQPtoQ(levelQ, levelP int, p1Q, p1P, p2Q Poly)

ModDownQPtoQ reduces the basis of a polynomial. Given a polynomial with coefficients in basis {Q0,Q1....Qlevel} and {P0,P1...Pj}, it reduces its basis from {Q0,Q1....Qlevel} and {P0,P1...Pj} to {Q0,Q1....Qlevel} and does a rounded integer division of the result by P.

func (*BasisExtender) ModDownQPtoQNTT

func (be *BasisExtender) ModDownQPtoQNTT(levelQ, levelP int, p1Q, p1P, p2Q Poly)

ModDownQPtoQNTT reduces the basis of a polynomial. Given a polynomial with coefficients in basis {Q0,Q1....Qi} and {P0,P1...Pj}, it reduces its basis from {Q0,Q1....Qi} and {P0,P1...Pj} to {Q0,Q1....Qi} and does a rounded integer division of the result by P. Inputs must be in the NTT domain.

func (*BasisExtender) ModUpPtoQ

func (be *BasisExtender) ModUpPtoQ(levelP, levelQ int, polP, polQ Poly)

ModUpPtoQ extends the RNS basis of a polynomial from P to PQ. Given a polynomial with coefficients in basis {P0,P1....Plevel}, it extends its basis from {P0,P1....Plevel} to {Q0,Q1...Qj}

func (*BasisExtender) ModUpQtoP

func (be *BasisExtender) ModUpQtoP(levelQ, levelP int, polQ, polP Poly)

ModUpQtoP extends the RNS basis of a polynomial from Q to QP. Given a polynomial with coefficients in basis {Q0,Q1....Qlevel}, it extends its basis from {Q0,Q1....Qlevel} to {Q0,Q1....Qlevel,P0,P1...Pj}

func (*BasisExtender) ShallowCopy

func (be *BasisExtender) ShallowCopy() *BasisExtender

ShallowCopy creates a shallow copy of this basis extender in which the read-only data-structures are shared with the receiver.

type Decomposer

type Decomposer struct {
	ModUpConstants [][][]ModUpConstants
	// contains filtered or unexported fields
}

Decomposer is a structure that stores the parameters of the arbitrary decomposer. This decomposer takes a p(x)_Q (in basis Q) and returns p(x) mod qi in basis QP, where qi = prod(Q_i) for 0<=i<=L, where L is the number of factors in P.

func NewDecomposer

func NewDecomposer(ringQ, ringP *Ring) (decomposer *Decomposer)

NewDecomposer creates a new Decomposer.

func (*Decomposer) DecomposeAndSplit

func (decomposer *Decomposer) DecomposeAndSplit(levelQ, levelP, nbPi, BaseRNSDecompositionVectorSize int, p0Q, p1Q, p1P Poly)

DecomposeAndSplit decomposes a polynomial p(x) in basis Q, reduces it modulo qi, and returns the result in basis QP separately.

type Dimensions

type Dimensions struct {
	Rows, Cols int
}

type DiscreteGaussian

type DiscreteGaussian struct {
	Sigma float64
	Bound float64
}

DiscreteGaussian represents the parameters of a discrete Gaussian distribution with standard deviation Sigma and bounds [-Bound, Bound].

func (DiscreteGaussian) MarshalJSON

func (d DiscreteGaussian) MarshalJSON() ([]byte, error)

func (DiscreteGaussian) Type

func (d DiscreteGaussian) Type() string

type DistributionParameters

type DistributionParameters interface {
	// Type returns a string representation of the distribution name.
	Type() string
	// contains filtered or unexported methods
}

DistributionParameters is an interface for distribution parameters in the ring. There are three implementation of this interface:

  • DiscreteGaussian for sampling polynomials with discretized gaussian coefficient of given standard deviation and bound.
  • Ternary for sampling polynomials with coefficients in [-1, 1].
  • Uniform for sampling polynomial with uniformly random coefficients in the ring.

func ParametersFromMap

func ParametersFromMap(distDef map[string]interface{}) (DistributionParameters, error)

type GaussianSampler

type GaussianSampler struct {
	// contains filtered or unexported fields
}

GaussianSampler keeps the state of a truncated Gaussian polynomial sampler.

func NewGaussianSampler

func NewGaussianSampler(prng sampling.PRNG, baseRing *Ring, X DiscreteGaussian, montgomery bool) (g *GaussianSampler)

NewGaussianSampler creates a new instance of GaussianSampler from a PRNG, a ring definition and the truncated Gaussian distribution parameters. Sigma is the desired standard deviation and bound is the maximum coefficient norm in absolute value.

func (*GaussianSampler) AtLevel

func (g *GaussianSampler) AtLevel(level int) Sampler

AtLevel returns an instance of the target GaussianSampler that operates at the target level. This instance is not thread safe and cannot be used concurrently to the base instance.

func (*GaussianSampler) Read

func (g *GaussianSampler) Read(pol Poly)

Read samples a truncated Gaussian polynomial on "pol" at the maximum level in the default ring, standard deviation and bound.

func (*GaussianSampler) ReadAndAdd

func (g *GaussianSampler) ReadAndAdd(pol Poly)

ReadAndAdd samples a truncated Gaussian polynomial at the given level for the receiver's default standard deviation and bound and adds it on "pol".

func (*GaussianSampler) ReadNew

func (g *GaussianSampler) ReadNew() (pol Poly)

ReadNew samples a new truncated Gaussian polynomial at the maximum level in the default ring, standard deviation and bound.

type Interpolator

type Interpolator struct {
	// contains filtered or unexported fields
}

Interpolator is a struct storing the necessary buffer and pre-computation for polynomial interpolation with coefficient in finite fields.

func NewInterpolator

func NewInterpolator(degree int, T uint64) (itp *Interpolator, err error)

NewInterpolator creates a new Interpolator. Returns an error if T is not prime or not congruent to 1 mod 2N, where N is the next power of two greater than degree+1.

func (*Interpolator) Interpolate

func (itp *Interpolator) Interpolate(roots []uint64) (coeffs []uint64)

Interpolate takes a list of roots the coefficients of P(roots) = 0 mod T.

func (*Interpolator) Lagrange

func (itp *Interpolator) Lagrange(x, y []uint64) (coeffs []uint64, err error)

Lagrange takes as input (x, y) and returns P(xi) = yi mod T.

type ModUpConstants

type ModUpConstants struct {
	// contains filtered or unexported fields
}

ModUpConstants stores the necessary parameters for RNS basis extension.

func GenModUpConstants

func GenModUpConstants(Q, P []uint64) ModUpConstants

GenModUpConstants generates the ModUpConstants for basis extension from Q to P and P to Q.

type NTTFriendlyPrimesGenerator

type NTTFriendlyPrimesGenerator struct {
	Size                           float64
	NextPrime, PrevPrime, NthRoot  uint64
	CheckNextPrime, CheckPrevPrime bool
}

NTTFriendlyPrimesGenerator is a struct used to generate NTT friendly primes.

func NewNTTFriendlyPrimesGenerator

func NewNTTFriendlyPrimesGenerator(BitSize, NthRoot uint64) NTTFriendlyPrimesGenerator

NewNTTFriendlyPrimesGenerator instantiates a new NTTFriendlyPrimesGenerator. Primes generated are of the form 2^{BitSize} +/- k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextAlternatingPrime

func (n *NTTFriendlyPrimesGenerator) NextAlternatingPrime() (uint64, error)

NextAlternatingPrime returns the next prime of the form 2^{BitSize} +/- k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextAlternatingPrimes

func (n *NTTFriendlyPrimesGenerator) NextAlternatingPrimes(k int) (primes []uint64, err error)

NextAlternatingPrimes returns the next k primes of the form 2^{BitSize} +/- k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextDownstreamPrime

func (n *NTTFriendlyPrimesGenerator) NextDownstreamPrime() (uint64, error)

NextDownstreamPrime returns the next prime of the form 2^{BitSize} - k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextDownstreamPrimes

func (n *NTTFriendlyPrimesGenerator) NextDownstreamPrimes(k int) (primes []uint64, err error)

NextDownstreamPrimes returns the next k primes of the form 2^{BitSize} - k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextUpstreamPrime

func (n *NTTFriendlyPrimesGenerator) NextUpstreamPrime() (uint64, error)

NextUpstreamPrime returns the next prime of the form 2^{BitSize} + k * {NthRoot} + 1.

func (*NTTFriendlyPrimesGenerator) NextUpstreamPrimes

func (n *NTTFriendlyPrimesGenerator) NextUpstreamPrimes(k int) (primes []uint64, err error)

NextUpstreamPrimes returns the next k primes of the form 2^{BitSize} + k * {NthRoot} + 1.

type NTTTable

type NTTTable struct {
	NthRoot       uint64   // Nthroot used for the NTT
	PrimitiveRoot uint64   // 2N-th primitive root
	RootsForward  []uint64 //powers of the 2N-th primitive root in Montgomery form (in bit-reversed order)
	RootsBackward []uint64 //powers of the inverse of the 2N-th primitive root in Montgomery form (in bit-reversed order)
	NInv          uint64   //[N^-1] mod Modulus in Montgomery form
}

NTTTable store all the constants that are specifically tied to the NTT.

type NumberTheoreticTransformer

type NumberTheoreticTransformer interface {
	Forward(p1, p2 []uint64)
	ForwardLazy(p1, p2 []uint64)
	Backward(p1, p2 []uint64)
	BackwardLazy(p1, p2 []uint64)
}

NumberTheoreticTransformer is an interface to provide flexibility on what type of NTT is used by the struct Ring.

func NewNumberTheoreticTransformerConjugateInvariant

func NewNumberTheoreticTransformerConjugateInvariant(r *SubRing, n int) NumberTheoreticTransformer

func NewNumberTheoreticTransformerStandard

func NewNumberTheoreticTransformerStandard(r *SubRing, n int) NumberTheoreticTransformer

type NumberTheoreticTransformerConjugateInvariant

type NumberTheoreticTransformerConjugateInvariant struct {
	// contains filtered or unexported fields
}

NumberTheoreticTransformerConjugateInvariant computes the NTT in the ring Z[X+X^-1]/(X^2N+1). Z[X+X^-1]/(X^2N+1) is a closed sub-ring of Z[X]/(X^2N+1). Note that the input polynomial only needs to be size N since the right half does not provide any additional information. See "Approximate Homomorphic Encryption over the Conjugate-invariant Ring", https://eprint.iacr.org/2018/952. The implemented approach is more efficient than the one proposed in the referenced work. It avoids the linear map Z[X + X^-1]/(X^2N + 1) <-> Z[X]/(X^N - 1) by instead directly computing the left half of the NTT of Z[X + X^-1]/(X^2N + 1) since the right half provides no additional information, which allows to (re)use nega-cyclic NTT.

func (NumberTheoreticTransformerConjugateInvariant) Backward

func (rntt NumberTheoreticTransformerConjugateInvariant) Backward(p1, p2 []uint64)

Backward writes the backward NTT in Z[X+X^-1]/(X^2N+1) of p1 on p2.

func (NumberTheoreticTransformerConjugateInvariant) BackwardLazy

func (rntt NumberTheoreticTransformerConjugateInvariant) BackwardLazy(p1, p2 []uint64)

BackwardLazy writes the backward NTT in Z[X+X^-1]/(X^2N+1) of p1 on p2. Returns values in the range [0, 2q-1].

func (NumberTheoreticTransformerConjugateInvariant) Forward

Forward writes the forward NTT in Z[X+X^-1]/(X^2N+1) of p1 on p2.

func (NumberTheoreticTransformerConjugateInvariant) ForwardLazy

func (rntt NumberTheoreticTransformerConjugateInvariant) ForwardLazy(p1, p2 []uint64)

ForwardLazy writes the forward NTT in Z[X+X^-1]/(X^2N+1) of p1 on p2. Returns values in the range [0, 2q-1].

type NumberTheoreticTransformerStandard

type NumberTheoreticTransformerStandard struct {
	// contains filtered or unexported fields
}

NumberTheoreticTransformerStandard computes the standard nega-cyclic NTT in the ring Z[X]/(X^N+1).

func (NumberTheoreticTransformerStandard) Backward

func (rntt NumberTheoreticTransformerStandard) Backward(p1, p2 []uint64)

Backward writes the backward NTT in Z[X]/(X^N+1) of p1 on p2.

func (NumberTheoreticTransformerStandard) BackwardLazy

func (rntt NumberTheoreticTransformerStandard) BackwardLazy(p1, p2 []uint64)

BackwardLazy writes the backward NTT in Z[X]/(X^N+1) p1 on p2. Returns values in the range [0, 2q-1].

func (NumberTheoreticTransformerStandard) Forward

func (rntt NumberTheoreticTransformerStandard) Forward(p1, p2 []uint64)

Forward writes the forward NTT in Z[X]/(X^N+1) of p1 on p2.

func (NumberTheoreticTransformerStandard) ForwardLazy

func (rntt NumberTheoreticTransformerStandard) ForwardLazy(p1, p2 []uint64)

ForwardLazy writes the forward NTT in Z[X]/(X^N+1) of p1 on p2. Returns values in the range [0, 2q-1].

type Parameters

type Parameters struct {
	// contains filtered or unexported fields
}

Parameters is a struct storing test parameters for the package Ring.

type Poly

type Poly struct {
	Coeffs structs.Matrix[uint64]
}

Poly is the structure that contains the coefficients of a polynomial.

func NewPoly

func NewPoly(N, Level int) (pol Poly)

NewPoly creates a new polynomial with N coefficients set to zero and Level+1 moduli.

func (Poly) BinarySize

func (pol Poly) BinarySize() (size int)

BinarySize returns the serialized size of the object in bytes.

func (*Poly) Copy

func (pol *Poly) Copy(p1 Poly)

Copy copies the coefficients of p1 on the target polynomial. This method does nothing if the underlying arrays are the same. This method will resize the target polynomial to the level of the input polynomial.

func (*Poly) CopyLvl

func (pol *Poly) CopyLvl(level int, p1 Poly)

CopyLvl copies the coefficients of p1 on the target polynomial. This method does nothing if the underlying arrays are the same. Expects the degree of both polynomials to be identical.

func (Poly) CopyNew

func (pol Poly) CopyNew() *Poly

CopyNew creates an exact copy of the target polynomial.

func (Poly) Equal

func (pol Poly) Equal(other *Poly) bool

Equal returns true if the receiver Poly is equal to the provided other Poly. This function checks for strict equality between the polynomial coefficients (i.e., it does not consider congruence as equality within the ring like `Ring.Equal` does).

func (Poly) Level

func (pol Poly) Level() int

Level returns the current number of moduli minus 1.

func (Poly) MarshalBinary

func (pol Poly) MarshalBinary() (p []byte, err error)

MarshalBinary encodes the object into a binary form on a newly allocated slice of bytes.

func (Poly) N

func (pol Poly) N() int

N returns the number of coefficients of the polynomial, which equals the degree of the Ring cyclotomic polynomial.

func (*Poly) ReadFrom

func (pol *Poly) ReadFrom(r io.Reader) (n int64, err error)

ReadFrom reads on the object from an io.Writer. It implements the io.ReaderFrom interface.

Unless r implements the buffer.Reader interface (see see lattigo/utils/buffer/reader.go), it will be wrapped into a bufio.Reader. Since this requires allocation, it is preferable to pass a buffer.Reader directly:

  • When reading multiple values from a io.Reader, it is preferable to first first wrap io.Reader in a pre-allocated bufio.Reader.
  • When reading from a var b []byte, it is preferable to pass a buffer.NewBuffer(b) as w (see lattigo/utils/buffer/buffer.go).

func (*Poly) Resize

func (pol *Poly) Resize(level int)

Resize resizes the level of the target polynomial to the provided level. If the provided level is larger than the current level, then allocates zero coefficients, otherwise dereferences the coefficients above the provided level.

func (*Poly) UnmarshalBinary

func (pol *Poly) UnmarshalBinary(p []byte) (err error)

UnmarshalBinary decodes a slice of bytes generated by MarshalBinary or WriteTo on the object.

func (Poly) WriteTo

func (pol Poly) WriteTo(w io.Writer) (n int64, err error)

WriteTo writes the object on an io.Writer. It implements the io.WriterTo interface, and will write exactly object.BinarySize() bytes on w.

Unless w implements the buffer.Writer interface (see lattigo/utils/buffer/writer.go), it will be wrapped into a bufio.Writer. Since this requires allocations, it is preferable to pass a buffer.Writer directly:

  • When writing multiple times to a io.Writer, it is preferable to first wrap the io.Writer in a pre-allocated bufio.Writer.
  • When writing to a pre-allocated var b []byte, it is preferable to pass buffer.NewBuffer(b) as w (see lattigo/utils/buffer/buffer.go).

func (Poly) Zero

func (pol Poly) Zero()

Zero sets all coefficients of the target polynomial to 0.

type RNSScalar

type RNSScalar []uint64

RNSScalar represents a scalar value in the Ring (i.e., a degree-0 polynomial) in RNS form.

type Ring

type Ring struct {
	SubRings []*SubRing

	// Product of the Moduli for each level
	ModulusAtLevel []*big.Int

	// Rescaling parameters (RNS division)
	RescaleConstants [][]uint64
	// contains filtered or unexported fields
}

Ring is a structure that keeps all the variables required to operate on a polynomial represented in this ring.

func NewRing

func NewRing(N int, Moduli []uint64) (r *Ring, err error)

NewRing creates a new RNS Ring with degree N and coefficient moduli Moduli with Standard NTT. N must be a power of two larger than 8. Moduli should be a non-empty []uint64 with distinct prime elements. All moduli must also be equal to 1 modulo 2*N. An error is returned with a nil *Ring in the case of non NTT-enabling parameters.

func NewRingConjugateInvariant

func NewRingConjugateInvariant(N int, Moduli []uint64) (r *Ring, err error)

NewRingConjugateInvariant creates a new RNS Ring with degree N and coefficient moduli Moduli with Conjugate Invariant NTT. N must be a power of two larger than 8. Moduli should be a non-empty []uint64 with distinct prime elements. All moduli must also be equal to 1 modulo 4*N. An error is returned with a nil *Ring in the case of non NTT-enabling parameters.

func NewRingFromType

func NewRingFromType(N int, Moduli []uint64, ringType Type) (r *Ring, err error)

NewRingFromType creates a new RNS Ring with degree N and coefficient moduli Moduli for which the type of NTT is determined by the ringType argument. If ringType==Standard, the ring is instantiated with standard NTT with the Nth root of unity 2*N. If ringType==ConjugateInvariant, the ring is instantiated with a ConjugateInvariant NTT with Nth root of unity 4*N. N must be a power of two larger than 8. Moduli should be a non-empty []uint64 with distinct prime elements. All moduli must also be equal to 1 modulo the root of unity. An error is returned with a nil *Ring in the case of non NTT-enabling parameters.

func NewRingWithCustomNTT

func NewRingWithCustomNTT(N int, ModuliChain []uint64, ntt func(*SubRing, int) NumberTheoreticTransformer, NthRoot int) (r *Ring, err error)

NewRingWithCustomNTT creates a new RNS Ring with degree N and coefficient moduli Moduli with user-defined NTT transform and primitive Nth root of unity. ModuliChain should be a non-empty []uint64 with distinct prime elements. All moduli must also be equal to 1 modulo the root of unity. N must be a power of two larger than 8. An error is returned with a nil *Ring in the case of non NTT-enabling parameters.

func (Ring) Add

func (r Ring) Add(p1, p2, p3 Poly)

Add evaluates p3 = p1 + p2 coefficient-wise in the ring.

func (Ring) AddDoubleRNSScalar

func (r Ring) AddDoubleRNSScalar(p1 Poly, scalar0, scalar1 RNSScalar, p2 Poly)

AddDoubleRNSScalar evaluates p2 = p1[:N/2] + scalar0 || p1[N/2] + scalar1 coefficient-wise in the ring, with the scalar values expressed in the CRT decomposition at a given level.

func (Ring) AddLazy

func (r Ring) AddLazy(p1, p2, p3 Poly)

AddLazy evaluates p3 = p1 + p2 coefficient-wise in the ring, with p3 in [0, 2*modulus-1].

func (Ring) AddScalar

func (r Ring) AddScalar(p1 Poly, scalar uint64, p2 Poly)

AddScalar evaluates p2 = p1 + scalar coefficient-wise in the ring.

func (Ring) AddScalarBigint

func (r Ring) AddScalarBigint(p1 Poly, scalar *big.Int, p2 Poly)

AddScalarBigint evaluates p2 = p1 + scalar coefficient-wise in the ring.

func (Ring) AtLevel

func (r Ring) AtLevel(level int) *Ring

AtLevel returns an instance of the target ring that operates at the target level. This instance is thread safe and can be use concurrently with the base ring.

func (Ring) Automorphism

func (r Ring) Automorphism(polIn Poly, gen uint64, polOut Poly)

Automorphism applies the automorphism X^{i} -> X^{i*gen} on a polynomial outside of the NTT domain. It must be noted that the result cannot be in-place.

func (Ring) AutomorphismNTT

func (r Ring) AutomorphismNTT(polIn Poly, gen uint64, polOut Poly)

AutomorphismNTT applies the automorphism X^{i} -> X^{i*gen} on a polynomial in the NTT domain. It must be noted that the result cannot be in-place.

func (Ring) AutomorphismNTTWithIndex

func (r Ring) AutomorphismNTTWithIndex(polIn Poly, index []uint64, polOut Poly)

AutomorphismNTTWithIndex applies the automorphism X^{i} -> X^{i*gen} on a polynomial in the NTT domain. `index` is the lookup table storing the mapping of the automorphism. It must be noted that the result cannot be in-place.

func (Ring) AutomorphismNTTWithIndexThenAddLazy

func (r Ring) AutomorphismNTTWithIndexThenAddLazy(polIn Poly, index []uint64, polOut Poly)

AutomorphismNTTWithIndexThenAddLazy applies the automorphism X^{i} -> X^{i*gen} on a polynomial in the NTT domain . `index` is the lookup table storing the mapping of the automorphism. The result of the automorphism is added on polOut.

func (Ring) BRedConstants

func (r Ring) BRedConstants() (BRC [][]uint64)

BRedConstants returns the concatenation of the Barrett constants of the target ring.

func (Ring) ConjugateInvariantRing

func (r Ring) ConjugateInvariantRing() (*Ring, error)

ConjugateInvariantRing returns the conjugate invariant ring of the receiver ring. If `r.Type()==ConjugateInvariant`, then the method returns the receiver. if `r.Type()==Standard`, then the method returns a ring with ring degree N/2. The returned Ring is a shallow copy of the receiver.

func (Ring) DivFloorByLastModulus

func (r Ring) DivFloorByLastModulus(p0, p1 Poly)

DivFloorByLastModulus divides (floored) the polynomial by its last modulus. Output poly level must be equal or one less than input level.

func (Ring) DivFloorByLastModulusMany

func (r Ring) DivFloorByLastModulusMany(nbRescales int, p0, buff, p1 Poly)

DivFloorByLastModulusMany divides (floored) sequentially nbRescales times the polynomial by its last modulus. Output poly level must be equal or nbRescales less than input level.

func (Ring) DivFloorByLastModulusManyNTT

func (r Ring) DivFloorByLastModulusManyNTT(nbRescales int, p0, buff, p1 Poly)

DivFloorByLastModulusManyNTT divides (floored) sequentially nbRescales times the polynomial by its last modulus. Input must be in the NTT domain. Output poly level must be equal or nbRescales less than input level.

func (Ring) DivFloorByLastModulusNTT

func (r Ring) DivFloorByLastModulusNTT(p0, buff, p1 Poly)

DivFloorByLastModulusNTT divides (floored) the polynomial by its last modulus. The input must be in the NTT domain. Output poly level must be equal or one less than input level.

func (Ring) DivRoundByLastModulus

func (r Ring) DivRoundByLastModulus(p0, p1 Poly)

DivRoundByLastModulus divides (rounded) the polynomial by its last modulus. The input must be in the NTT domain. Output poly level must be equal or one less than input level.

func (Ring) DivRoundByLastModulusMany

func (r Ring) DivRoundByLastModulusMany(nbRescales int, p0, buff, p1 Poly)

DivRoundByLastModulusMany divides (rounded) sequentially nbRescales times the polynomial by its last modulus. Output poly level must be equal or nbRescales less than input level.

func (Ring) DivRoundByLastModulusManyNTT

func (r Ring) DivRoundByLastModulusManyNTT(nbRescales int, p0, buff, p1 Poly)

DivRoundByLastModulusManyNTT divides (rounded) sequentially nbRescales times the polynomial by its last modulus. The input must be in the NTT domain. Output poly level must be equal or nbRescales less than input level.

func (Ring) DivRoundByLastModulusNTT

func (r Ring) DivRoundByLastModulusNTT(p0, buff, p1 Poly)

DivRoundByLastModulusNTT divides (rounded) the polynomial by its last modulus. The input must be in the NTT domain. Output poly level must be equal or one less than input level.

func (Ring) Equal

func (r Ring) Equal(p1, p2 Poly) bool

Equal checks if p1 = p2 in the given Ring.

func (Ring) EvalPolyScalar

func (r Ring) EvalPolyScalar(p1 []Poly, scalar uint64, p2 Poly)

EvalPolyScalar evaluate p2 = p1(scalar) coefficient-wise in the ring.

func (Ring) FoldStandardToConjugateInvariant

func (r Ring) FoldStandardToConjugateInvariant(polyStandard Poly, permuteNTTIndexInv []uint64, polyConjugateInvariant Poly)

FoldStandardToConjugateInvariant folds [X]/(X^N+1) to [X+X^-1]/(X^N+1) in compressed form (N/2 coefficients). Requires degree(polyConjugateInvariant) = 2*degree(polyStandard). Requires that polyStandard and polyConjugateInvariant share the same moduli.

func (Ring) IMForm

func (r Ring) IMForm(p1, p2 Poly)

IMForm evaluates p2 = p1 * 2^64 coefficient-wise in the ring.

func (Ring) INTT

func (r Ring) INTT(p1, p2 Poly)

INTT evaluates p2 = INTT(p1).

func (Ring) INTTLazy

func (r Ring) INTTLazy(p1, p2 Poly)

INTTLazy evaluates p2 = INTT(p1) with p2 in [0, 2*modulus-1].

func (*Ring) Inverse

func (r *Ring) Inverse(a RNSScalar)

Inverse computes the modular inverse of a scalar a expressed in a CRT decomposition. The inversion is done in-place and assumes that a is in Montgomery form.

func (Ring) Level

func (r Ring) Level() int

Level returns the level of the current ring.

func (Ring) Log2OfStandardDeviation

func (r Ring) Log2OfStandardDeviation(poly Poly) (std float64)

Log2OfStandardDeviation returns base 2 logarithm of the standard deviation of the coefficients of the polynomial.

func (Ring) LogModuli

func (r Ring) LogModuli() (logmod float64)

LogModuli returns the size of the extended modulus P in bits

func (Ring) LogN

func (r Ring) LogN() int

LogN returns log2(ring degree).

func (Ring) MForm

func (r Ring) MForm(p1, p2 Poly)

MForm evaluates p2 = p1 * (2^64)^-1 coefficient-wise in the ring.

func (Ring) MFormLazy

func (r Ring) MFormLazy(p1, p2 Poly)

MFormLazy evaluates p2 = p1 * (2^64)^-1 coefficient-wise in the ring with p2 in [0, 2*modulus-1].

func (*Ring) MFormRNSScalar

func (r *Ring) MFormRNSScalar(s1, s2 RNSScalar)

MFormRNSScalar switches an RNS scalar to the Montgomery domain. s2 = s1<<64 mod Q

func (Ring) MRedConstants

func (r Ring) MRedConstants() (MRC []uint64)

MRedConstants returns the concatenation of the Montgomery constants of the target ring.

func (Ring) MarshalBinary

func (r Ring) MarshalBinary() (data []byte, err error)

MarshalBinary encodes the object into a binary form on a newly allocated slice of bytes.

func (Ring) MarshalJSON

func (r Ring) MarshalJSON() (data []byte, err error)

MarshalJSON encodes the object into a binary form on a newly allocated slice of bytes with the json codec.

func (Ring) MaxLevel

func (r Ring) MaxLevel() int

MaxLevel returns the maximum level allowed by the ring (#NbModuli -1).

func (Ring) ModuliChain

func (r Ring) ModuliChain() (moduli []uint64)

ModuliChain returns the list of primes in the modulus chain.

func (Ring) ModuliChainLength

func (r Ring) ModuliChainLength() int

ModuliChainLength returns the number of primes in the RNS basis of the ring.

func (Ring) Modulus

func (r Ring) Modulus() *big.Int

Modulus returns the modulus of the target ring at the currently set level in *big.Int.

func (Ring) MulByVectorMontgomery

func (r Ring) MulByVectorMontgomery(p1 Poly, vector []uint64, p2 Poly)

MulByVectorMontgomery evaluates p2 = p1 * vector coefficient-wise in the ring.

func (Ring) MulByVectorMontgomeryThenAddLazy

func (r Ring) MulByVectorMontgomeryThenAddLazy(p1 Poly, vector []uint64, p2 Poly)

MulByVectorMontgomeryThenAddLazy evaluates p2 = p2 + p1 * vector coefficient-wise in the ring.

func (Ring) MulCoeffsBarrett

func (r Ring) MulCoeffsBarrett(p1, p2, p3 Poly)

MulCoeffsBarrett evaluates p3 = p1 * p2 coefficient-wise in the ring, with Barrett reduction.

func (Ring) MulCoeffsBarrettLazy

func (r Ring) MulCoeffsBarrettLazy(p1, p2, p3 Poly)

MulCoeffsBarrettLazy evaluates p3 = p1 * p2 coefficient-wise in the ring, with Barrett reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsBarrettThenAdd

func (r Ring) MulCoeffsBarrettThenAdd(p1, p2, p3 Poly)

MulCoeffsBarrettThenAdd evaluates p3 = p3 + p1 * p2 coefficient-wise in the ring, with Barrett reduction.

func (Ring) MulCoeffsBarrettThenAddLazy

func (r Ring) MulCoeffsBarrettThenAddLazy(p1, p2, p3 Poly)

MulCoeffsBarrettThenAddLazy evaluates p3 = p1 * p2 coefficient-wise in the ring, with Barrett reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsMontgomery

func (r Ring) MulCoeffsMontgomery(p1, p2, p3 Poly)

MulCoeffsMontgomery evaluates p3 = p1 * p2 coefficient-wise in the ring, with Montgomery reduction.

func (Ring) MulCoeffsMontgomeryLazy

func (r Ring) MulCoeffsMontgomeryLazy(p1, p2, p3 Poly)

MulCoeffsMontgomeryLazy evaluates p3 = p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsMontgomeryLazyThenAddLazy

func (r Ring) MulCoeffsMontgomeryLazyThenAddLazy(p1, p2, p3 Poly)

MulCoeffsMontgomeryLazyThenAddLazy evaluates p3 = p3 + p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 3*modulus-2].

func (Ring) MulCoeffsMontgomeryLazyThenNeg

func (r Ring) MulCoeffsMontgomeryLazyThenNeg(p1, p2, p3 Poly)

MulCoeffsMontgomeryLazyThenNeg evaluates p3 = -p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsMontgomeryLazyThenSubLazy

func (r Ring) MulCoeffsMontgomeryLazyThenSubLazy(p1, p2, p3 Poly)

MulCoeffsMontgomeryLazyThenSubLazy evaluates p3 = p3 - p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 3*modulus-2].

func (Ring) MulCoeffsMontgomeryThenAdd

func (r Ring) MulCoeffsMontgomeryThenAdd(p1, p2, p3 Poly)

MulCoeffsMontgomeryThenAdd evaluates p3 = p3 + p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsMontgomeryThenAddLazy

func (r Ring) MulCoeffsMontgomeryThenAddLazy(p1, p2, p3 Poly)

MulCoeffsMontgomeryThenAddLazy evaluates p3 = p3 + p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulCoeffsMontgomeryThenSub

func (r Ring) MulCoeffsMontgomeryThenSub(p1, p2, p3 Poly)

MulCoeffsMontgomeryThenSub evaluates p3 = p3 - p1 * p2 coefficient-wise in the ring, with Montgomery reduction.

func (Ring) MulCoeffsMontgomeryThenSubLazy

func (r Ring) MulCoeffsMontgomeryThenSubLazy(p1, p2, p3 Poly)

MulCoeffsMontgomeryThenSubLazy evaluates p3 = p3 - p1 * p2 coefficient-wise in the ring, with Montgomery reduction, with p3 in [0, 2*modulus-1].

func (Ring) MulDoubleRNSScalar

func (r Ring) MulDoubleRNSScalar(p1 Poly, scalar0, scalar1 RNSScalar, p2 Poly)

MulDoubleRNSScalar evaluates p2 = p1[:N/2] * scalar0 || p1[N/2] * scalar1 coefficient-wise in the ring, with the scalar values expressed in the CRT decomposition at a given level.

func (Ring) MulDoubleRNSScalarThenAdd

func (r Ring) MulDoubleRNSScalarThenAdd(p1 Poly, scalar0, scalar1 RNSScalar, p2 Poly)

MulDoubleRNSScalarThenAdd evaluates p2 = p2 + p1[:N/2] * scalar0 || p1[N/2] * scalar1 coefficient-wise in the ring, with the scalar values expressed in the CRT decomposition at a given level.

func (*Ring) MulRNSScalar

func (r *Ring) MulRNSScalar(s1, s2, sout RNSScalar)

MulRNSScalar multiplies s1 and s2 and stores the result in sout. Multiplication is operated with Montgomery.

func (Ring) MulRNSScalarMontgomery

func (r Ring) MulRNSScalarMontgomery(p1 Poly, scalar RNSScalar, p2 Poly)

MulRNSScalarMontgomery evaluates p2 = p1 * scalar coefficient-wise in the ring, with a scalar value expressed in the CRT decomposition at a given level. It assumes the scalar decomposition to be in Montgomery form.

func (Ring) MulScalar

func (r Ring) MulScalar(p1 Poly, scalar uint64, p2 Poly)

MulScalar evaluates p2 = p1 * scalar coefficient-wise in the ring.

func (Ring) MulScalarBigint

func (r Ring) MulScalarBigint(p1 Poly, scalar *big.Int, p2 Poly)

MulScalarBigint evaluates p2 = p1 * scalar coefficient-wise in the ring.

func (Ring) MulScalarBigintThenAdd

func (r Ring) MulScalarBigintThenAdd(p1 Poly, scalar *big.Int, p2 Poly)

MulScalarBigintThenAdd evaluates p2 = p1 * scalar coefficient-wise in the ring.

func (Ring) MulScalarThenAdd

func (r Ring) MulScalarThenAdd(p1 Poly, scalar uint64, p2 Poly)

MulScalarThenAdd evaluates p2 = p2 + p1 * scalar coefficient-wise in the ring.

func (Ring) MulScalarThenSub

func (r Ring) MulScalarThenSub(p1 Poly, scalar uint64, p2 Poly)

MulScalarThenSub evaluates p2 = p2 - p1 * scalar coefficient-wise in the ring.

func (Ring) MultByMonomial

func (r Ring) MultByMonomial(p1 Poly, k int, p2 Poly)

MultByMonomial evaluates p2 = p1 * X^k coefficient-wise in the ring.

func (Ring) N

func (r Ring) N() int

N returns the ring degree.

func (Ring) NTT

func (r Ring) NTT(p1, p2 Poly)

NTT evaluates p2 = NTT(P1).

func (Ring) NTTLazy

func (r Ring) NTTLazy(p1, p2 Poly)

NTTLazy evaluates p2 = NTT(p1) with p2 in [0, 2*modulus-1].

func (Ring) Neg

func (r Ring) Neg(p1, p2 Poly)

Neg evaluates p2 = -p1 coefficient-wise in the ring.

func (*Ring) NegRNSScalar

func (r *Ring) NegRNSScalar(s1, s2 RNSScalar)

NegRNSScalar evaluates s2 = -s1.

func (Ring) NewMonomialXi

func (r Ring) NewMonomialXi(i int) (p Poly)

NewMonomialXi returns a polynomial X^{i}.

func (Ring) NewPoly

func (r Ring) NewPoly() Poly

NewPoly creates a new polynomial with all coefficients set to 0.

func (*Ring) NewRNSScalar

func (r *Ring) NewRNSScalar() RNSScalar

NewRNSScalar creates a new Scalar value.

func (*Ring) NewRNSScalarFromBigint

func (r *Ring) NewRNSScalarFromBigint(v *big.Int) (rns RNSScalar)

NewRNSScalarFromBigint creates a new Scalar initialized with value v.

func (*Ring) NewRNSScalarFromUInt64

func (r *Ring) NewRNSScalarFromUInt64(v uint64) (rns RNSScalar)

NewRNSScalarFromUInt64 creates a new Scalar initialized with value v.

func (Ring) NthRoot

func (r Ring) NthRoot() uint64

NthRoot returns the multiplicative order of the primitive root.

func (Ring) PadDefaultRingToConjugateInvariant

func (r Ring) PadDefaultRingToConjugateInvariant(polyStandard Poly, IsNTT bool, polyConjugateInvariant Poly)

PadDefaultRingToConjugateInvariant converts a polynomial in Z[X]/(X^N +1) to a polynomial in Z[X+X^-1]/(X^2N+1).

func (Ring) PolyToBigint

func (r Ring) PolyToBigint(p1 Poly, gap int, coeffsBigint []*big.Int)

PolyToBigint reconstructs p1 and returns the result in an array of Int. gap defines coefficients X^{i*gap} that will be reconstructed. For example, if gap = 1, then all coefficients are reconstructed, while if gap = 2 then only coefficients X^{2*i} are reconstructed.

func (Ring) PolyToBigintCentered

func (r Ring) PolyToBigintCentered(p1 Poly, gap int, coeffsBigint []*big.Int)

PolyToBigintCentered reconstructs p1 and returns the result in an array of Int. Coefficients are centered around Q/2 gap defines coefficients X^{i*gap} that will be reconstructed. For example, if gap = 1, then all coefficients are reconstructed, while if gap = 2 then only coefficients X^{2*i} are reconstructed.

func (Ring) PolyToString

func (r Ring) PolyToString(p1 Poly) []string

PolyToString reconstructs p1 and returns the result in an array of string.

func (Ring) Reduce

func (r Ring) Reduce(p1, p2 Poly)

Reduce evaluates p2 = p1 coefficient-wise mod modulus in the ring.

func (Ring) ReduceLazy

func (r Ring) ReduceLazy(p1, p2 Poly)

ReduceLazy evaluates p2 = p1 coefficient-wise mod modulus in the ring, with p2 in [0, 2*modulus-1].

func (Ring) SetCoefficientsBigint

func (r Ring) SetCoefficientsBigint(coeffs []*big.Int, p1 Poly)

SetCoefficientsBigint sets the coefficients of p1 from an array of Int variables.

func (Ring) Shift

func (r Ring) Shift(p1 Poly, k int, p2 Poly)

Shift evaluates p2 = p2<<<k coefficient-wise in the ring.

func (Ring) StandardRing

func (r Ring) StandardRing() (*Ring, error)

StandardRing returns the standard ring of the receiver ring. If `r.Type()==Standard`, then the method returns the receiver. if `r.Type()==ConjugateInvariant`, then the method returns a ring with ring degree 2N. The returned Ring is a shallow copy of the receiver.

func (Ring) Sub

func (r Ring) Sub(p1, p2, p3 Poly)

Sub evaluates p3 = p1 - p2 coefficient-wise in the ring.

func (Ring) SubDoubleRNSScalar

func (r Ring) SubDoubleRNSScalar(p1 Poly, scalar0, scalar1 RNSScalar, p2 Poly)

SubDoubleRNSScalar evaluates p2 = p1[:N/2] - scalar0 || p1[N/2] - scalar1 coefficient-wise in the ring, with the scalar values expressed in the CRT decomposition at a given level.

func (Ring) SubLazy

func (r Ring) SubLazy(p1, p2, p3 Poly)

SubLazy evaluates p3 = p1 - p2 coefficient-wise in the ring, with p3 in [0, 2*modulus-1].

func (*Ring) SubRNSScalar

func (r *Ring) SubRNSScalar(s1, s2, sout RNSScalar)

SubRNSScalar subtracts s2 to s1 and stores the result in sout.

func (Ring) SubScalar

func (r Ring) SubScalar(p1 Poly, scalar uint64, p2 Poly)

SubScalar evaluates p2 = p1 - scalar coefficient-wise in the ring.

func (Ring) SubScalarBigint

func (r Ring) SubScalarBigint(p1 Poly, scalar *big.Int, p2 Poly)

SubScalarBigint evaluates p2 = p1 - scalar coefficient-wise in the ring.

func (*Ring) Type

func (r *Ring) Type() Type

Type returns the Type of the first subring which might be either `Standard` or `ConjugateInvariant`.

func (Ring) UnfoldConjugateInvariantToStandard

func (r Ring) UnfoldConjugateInvariantToStandard(polyConjugateInvariant, polyStandard Poly)

UnfoldConjugateInvariantToStandard maps the compressed representation (N/2 coefficients) of Z_Q[X+X^-1]/(X^2N + 1) to full representation in Z_Q[X]/(X^2N+1). Requires degree(polyConjugateInvariant) = 2*degree(polyStandard). Requires that polyStandard and polyConjugateInvariant share the same moduli.

func (*Ring) UnmarshalBinary

func (r *Ring) UnmarshalBinary(data []byte) (err error)

UnmarshalBinary decodes a slice of bytes generated by MarshalBinary or MarshalJSON on the object.

func (*Ring) UnmarshalJSON

func (r *Ring) UnmarshalJSON(data []byte) (err error)

UnmarshalJSON decodes a slice of bytes generated by MarshalJSON or MarshalBinary on the object.

type Sampler

type Sampler interface {
	Read(pol Poly)
	ReadNew() (pol Poly)
	ReadAndAdd(pol Poly)
	AtLevel(level int) Sampler
}

Sampler is an interface for random polynomial samplers. It has a single Read method which takes as argument the polynomial to be populated according to the Sampler's distribution.

func NewSampler

func NewSampler(prng sampling.PRNG, baseRing *Ring, X DistributionParameters, montgomery bool) (Sampler, error)

type SubRing

type SubRing struct {

	// Polynomial nb.Coefficients
	N int

	// Modulus
	Modulus uint64

	// Unique factors of Modulus-1
	Factors []uint64

	// 2^bit_length(Modulus) - 1
	Mask uint64

	// Fast reduction constants
	BRedConstant []uint64 // Barrett Reduction
	MRedConstant uint64   // Montgomery Reduction

	*NTTTable // NTT related constants
	// contains filtered or unexported fields
}

SubRing is a struct storing precomputation for fast modular reduction and NTT for a given modulus.

func NewSubRing

func NewSubRing(N int, Modulus uint64) (s *SubRing, err error)

NewSubRing creates a new SubRing with the standard NTT. NTT constants still need to be generated using .GenNTTConstants(NthRoot uint64).

func NewSubRingWithCustomNTT

func NewSubRingWithCustomNTT(N int, Modulus uint64, ntt func(*SubRing, int) NumberTheoreticTransformer, NthRoot int) (s *SubRing, err error)

NewSubRingWithCustomNTT creates a new SubRing with degree N and modulus Modulus with user-defined NTT transform and primitive Nth root of unity. Modulus should be equal to 1 modulo the root of unity. N must be a power of two larger than 8. An error is returned with a nil *SubRing in the case of non NTT-enabling parameters.

func (*SubRing) Add

func (s *SubRing) Add(p1, p2, p3 []uint64)

Add evaluates p3 = p1 + p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddLazy

func (s *SubRing) AddLazy(p1, p2, p3 []uint64)

AddLazy evaluates p3 = p1 + p2. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddLazyThenMulScalarMontgomery

func (s *SubRing) AddLazyThenMulScalarMontgomery(p1, p2 []uint64, scalarMont uint64, p3 []uint64)

AddLazyThenMulScalarMontgomery evaluates p3 = (p1+p2)*scalarMont (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddScalar

func (s *SubRing) AddScalar(p1 []uint64, scalar uint64, p2 []uint64)

AddScalar evaluates p2 = p1 + scalar (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddScalarLazy

func (s *SubRing) AddScalarLazy(p1 []uint64, scalar uint64, p2 []uint64)

AddScalarLazy evaluates p2 = p1 + scalar. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddScalarLazyThenMulScalarMontgomery

func (s *SubRing) AddScalarLazyThenMulScalarMontgomery(p1 []uint64, scalar0, scalarMont1 uint64, p2 []uint64)

AddScalarLazyThenMulScalarMontgomery evaluates p3 = (scalarMont0+p2)*scalarMont1 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) AddScalarLazyThenNegTwoModulusLazy

func (s *SubRing) AddScalarLazyThenNegTwoModulusLazy(p1 []uint64, scalar uint64, p2 []uint64)

AddScalarLazyThenNegTwoModulusLazy evaluates p2 = 2*modulus - p1 + scalar. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) IMForm

func (s *SubRing) IMForm(p1, p2 []uint64)

IMForm evaluates p2 = p1 * (2^64)^-1 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) INTT

func (s *SubRing) INTT(p1, p2 []uint64)

INTT evaluates p2 = INTT(p1).

func (*SubRing) INTTLazy

func (s *SubRing) INTTLazy(p1, p2 []uint64)

INTTLazy evaluates p2 = INTT(p1) with p2 in [0, 2*modulus-1].

func (*SubRing) MForm

func (s *SubRing) MForm(p1, p2 []uint64)

MForm evaluates p2 = p1 * 2^64 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MFormLazy

func (s *SubRing) MFormLazy(p1, p2 []uint64)

MFormLazy evaluates p2 = p1 * 2^64 (mod modulus) with p2 in the range [0, 2*modulus-1]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsBarrett

func (s *SubRing) MulCoeffsBarrett(p1, p2, p3 []uint64)

MulCoeffsBarrett evaluates p3 = p1*p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsBarrettLazy

func (s *SubRing) MulCoeffsBarrettLazy(p1, p2, p3 []uint64)

MulCoeffsBarrettLazy evaluates p3 = p1*p2 (mod modulus) with p3 in [0, 2*modulus-1]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsBarrettThenAdd

func (s *SubRing) MulCoeffsBarrettThenAdd(p1, p2, p3 []uint64)

MulCoeffsBarrettThenAdd evaluates p3 = p3 + (p1*p2) (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsBarrettThenAddLazy

func (s *SubRing) MulCoeffsBarrettThenAddLazy(p1, p2, p3 []uint64)

MulCoeffsBarrettThenAddLazy evaluates p3 = p3 + p1*p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsLazy

func (s *SubRing) MulCoeffsLazy(p1, p2, p3 []uint64)

MulCoeffsLazy evaluates p3 = p1*p2. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsLazyThenAddLazy

func (s *SubRing) MulCoeffsLazyThenAddLazy(p1, p2, p3 []uint64)

MulCoeffsLazyThenAddLazy evaluates p3 = p3 + p1*p2. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomery

func (s *SubRing) MulCoeffsMontgomery(p1, p2, p3 []uint64)

MulCoeffsMontgomery evaluates p3 = p1*p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryLazy

func (s *SubRing) MulCoeffsMontgomeryLazy(p1, p2, p3 []uint64)

MulCoeffsMontgomeryLazy evaluates p3 = p1*p2 (mod modulus) with p3 in range [0, 2*modulus-1]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryLazyThenAddLazy

func (s *SubRing) MulCoeffsMontgomeryLazyThenAddLazy(p1, p2, p3 []uint64)

MulCoeffsMontgomeryLazyThenAddLazy evaluates p3 = p3 + p1*p2 (mod modulus) with p3 in range [0, 3modulus-2]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryLazyThenNeg

func (s *SubRing) MulCoeffsMontgomeryLazyThenNeg(p1, p2, p3 []uint64)

MulCoeffsMontgomeryLazyThenNeg evaluates p3 = - p1*p2 (mod modulus) with p3 in range [0, 2*modulus-2]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryLazyThenSubLazy

func (s *SubRing) MulCoeffsMontgomeryLazyThenSubLazy(p1, p2, p3 []uint64)

MulCoeffsMontgomeryLazyThenSubLazy evaluates p3 = p3 - p1*p2 (mod modulus) with p3 in range [0, 3*modulus-2]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryThenAdd

func (s *SubRing) MulCoeffsMontgomeryThenAdd(p1, p2, p3 []uint64)

MulCoeffsMontgomeryThenAdd evaluates p3 = p3 + (p1*p2) (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryThenAddLazy

func (s *SubRing) MulCoeffsMontgomeryThenAddLazy(p1, p2, p3 []uint64)

MulCoeffsMontgomeryThenAddLazy evaluates p3 = p3 + (p1*p2 (mod modulus)). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryThenSub

func (s *SubRing) MulCoeffsMontgomeryThenSub(p1, p2, p3 []uint64)

MulCoeffsMontgomeryThenSub evaluates p3 = p3 - p1*p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulCoeffsMontgomeryThenSubLazy

func (s *SubRing) MulCoeffsMontgomeryThenSubLazy(p1, p2, p3 []uint64)

MulCoeffsMontgomeryThenSubLazy evaluates p3 = p3 - p1*p2 (mod modulus) with p3 in range [0, 2*modulus-2]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulScalarMontgomery

func (s *SubRing) MulScalarMontgomery(p1 []uint64, scalarMont uint64, p2 []uint64)

MulScalarMontgomery evaluates p2 = p1*scalarMont (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulScalarMontgomeryLazy

func (s *SubRing) MulScalarMontgomeryLazy(p1 []uint64, scalarMont uint64, p2 []uint64)

MulScalarMontgomeryLazy evaluates p2 = p1*scalarMont (mod modulus) with p2 in range [0, 2*modulus-1]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulScalarMontgomeryThenAdd

func (s *SubRing) MulScalarMontgomeryThenAdd(p1 []uint64, scalarMont uint64, p2 []uint64)

MulScalarMontgomeryThenAdd evaluates p2 = p2 + p1*scalarMont (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) MulScalarMontgomeryThenAddScalar

func (s *SubRing) MulScalarMontgomeryThenAddScalar(p1 []uint64, scalar0, scalarMont1 uint64, p2 []uint64)

MulScalarMontgomeryThenAddScalar evaluates p2 = scalar + p1*scalarMont (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) NTT

func (s *SubRing) NTT(p1, p2 []uint64)

NTT evaluates p2 = NTT(p1).

func (*SubRing) NTTLazy

func (s *SubRing) NTTLazy(p1, p2 []uint64)

NTTLazy evaluates p2 = NTT(p1) with p2 in [0, 2*modulus-1].

func (*SubRing) Neg

func (s *SubRing) Neg(p1, p2 []uint64)

Neg evaluates p2 = -p1 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) Reduce

func (s *SubRing) Reduce(p1, p2 []uint64)

Reduce evaluates p2 = p1 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) ReduceLazy

func (s *SubRing) ReduceLazy(p1, p2 []uint64)

ReduceLazy evaluates p2 = p1 (mod modulus) with p2 in range [0, 2*modulus-1]. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) Sub

func (s *SubRing) Sub(p1, p2, p3 []uint64)

Sub evaluates p3 = p1 - p2 (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) SubLazy

func (s *SubRing) SubLazy(p1, p2, p3 []uint64)

SubLazy evaluates p3 = p1 - p2. Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) SubScalar

func (s *SubRing) SubScalar(p1 []uint64, scalar uint64, p2 []uint64)

SubScalar evaluates p2 = p1 - scalar (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) SubThenMulScalarMontgomeryTwoModulus

func (s *SubRing) SubThenMulScalarMontgomeryTwoModulus(p1, p2 []uint64, scalarMont uint64, p3 []uint64)

SubThenMulScalarMontgomeryTwoModulus evaluates p3 = (p1 + twomodulus - p2) * scalarMont (mod modulus). Iteration is done with respect to len(p1). All input must have a size which is a multiple of 8.

func (*SubRing) Type

func (s *SubRing) Type() Type

Type returns the Type of subring which might be either `Standard` or `ConjugateInvariant`.

type Ternary

type Ternary struct {
	P float64
	H int
}

Ternary represent the parameters of a distribution with coefficients in [-1, 0, 1]. Only one of its field must be set to a non-zero value:

  • If P is set, each coefficient in the polynomial is sampled in [-1, 0, 1] with probabilities [0.5*P, 1-P, 0.5*P].
  • if H is set, the coefficients are sampled uniformly in the set of ternary polynomials with H non-zero coefficients (i.e., of hamming weight H).

func (Ternary) MarshalJSON

func (d Ternary) MarshalJSON() ([]byte, error)

func (Ternary) Type

func (d Ternary) Type() string

type TernarySampler

type TernarySampler struct {
	// contains filtered or unexported fields
}

TernarySampler keeps the state of a polynomial sampler in the ternary distribution.

func NewTernarySampler

func NewTernarySampler(prng sampling.PRNG, baseRing *Ring, X Ternary, montgomery bool) (ts *TernarySampler, err error)

NewTernarySampler creates a new instance of TernarySampler from a PRNG, the ring definition and the distribution parameters (see type Ternary). If "montgomery" is set to true, polynomials read from this sampler are in Montgomery form.

func (*TernarySampler) AtLevel

func (ts *TernarySampler) AtLevel(level int) Sampler

AtLevel returns an instance of the target TernarySampler to sample at the given level. The returned sampler cannot be used concurrently to the original sampler.

func (*TernarySampler) Read

func (ts *TernarySampler) Read(pol Poly)

Read samples a polynomial into pol.

func (*TernarySampler) ReadAndAdd

func (ts *TernarySampler) ReadAndAdd(pol Poly)

func (*TernarySampler) ReadNew

func (ts *TernarySampler) ReadNew() (pol Poly)

ReadNew allocates and samples a polynomial at the max level.

type Type

type Type int

Type is the type of ring used by the cryptographic scheme

func (Type) MarshalJSON

func (rt Type) MarshalJSON() ([]byte, error)

MarshalJSON marshals the receiver Type into a JSON []byte

func (Type) String

func (rt Type) String() string

String returns the string representation of the ring Type

func (*Type) UnmarshalJSON

func (rt *Type) UnmarshalJSON(b []byte) error

UnmarshalJSON reads a JSON byte slice into the receiver Type

type Uniform

type Uniform struct{}

Uniform represents the parameters of a uniform distribution i.e., with coefficients uniformly distributed in the given ring.

func (Uniform) MarshalJSON

func (d Uniform) MarshalJSON() ([]byte, error)

func (Uniform) Type

func (d Uniform) Type() string

type UniformSampler

type UniformSampler struct {
	// contains filtered or unexported fields
}

UniformSampler wraps a util.PRNG and represents the state of a sampler of uniform polynomials.

func NewUniformSampler

func NewUniformSampler(prng sampling.PRNG, baseRing *Ring) (u *UniformSampler)

NewUniformSampler creates a new instance of UniformSampler from a PRNG and ring definition.

func (*UniformSampler) AtLevel

func (u *UniformSampler) AtLevel(level int) Sampler

AtLevel returns an instance of the target UniformSampler to sample at the given level. The returned sampler cannot be used concurrently to the original sampler.

func (*UniformSampler) Read

func (u *UniformSampler) Read(pol Poly)

func (*UniformSampler) ReadAndAdd

func (u *UniformSampler) ReadAndAdd(pol Poly)

func (*UniformSampler) ReadNew

func (u *UniformSampler) ReadNew() (pol Poly)

ReadNew generates a new polynomial with coefficients following a uniform distribution over [0, Qi-1]. Polynomial is created at the max level.

func (*UniformSampler) WithPRNG

func (u *UniformSampler) WithPRNG(prng sampling.PRNG) *UniformSampler

Directories

Path Synopsis
Package ringqp is implements a wrapper for both the ringQ and ringP.
Package ringqp is implements a wrapper for both the ringQ and ringP.

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