ristretto255

package module
Version: v0.1.2 Latest Latest
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Published: Nov 26, 2019 License: BSD-3-Clause Imports: 7 Imported by: 32

README

ristretto255

GoDoc

Package ristretto255 implements draft-hdevalence-cfrg-ristretto-01.

Documentation

Overview

Package ristretto255 implements the group of prime order

2**252 + 27742317777372353535851937790883648493

as specified in draft-hdevalence-cfrg-ristretto-01.

All operations are constant time unless otherwise specified.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Element

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

Element is an element of the ristretto255 prime-order group.

func NewElement

func NewElement() *Element

NewElement returns a new Element set to the identity value.

func (*Element) Add

func (e *Element) Add(p, q *Element) *Element

Add sets e = p + q, and returns e.

func (*Element) Base

func (e *Element) Base() *Element

Base sets e to the canonical generator specified in draft-hdevalence-cfrg-ristretto-01, Section 3, and returns e.

func (*Element) Decode

func (e *Element) Decode(in []byte) error

Decode sets e to the decoded value of in. If in is not a 32 byte canonical encoding, Decode returns an error, and the receiver is unchanged.

func (*Element) Encode

func (e *Element) Encode(b []byte) []byte

Encode appends the 32 bytes canonical encoding of e to b and returns the result.

func (*Element) Equal

func (e *Element) Equal(ee *Element) int

Equal returns 1 if e is equivalent to ee, and 0 otherwise.

Note that Elements must not be compared in any other way.

func (*Element) FromUniformBytes

func (e *Element) FromUniformBytes(b []byte) *Element

FromUniformBytes maps the 64-byte slice b to e uniformly and deterministically, and returns e. This can be used for hash-to-group operations or to obtain a random element.

func (*Element) MarshalText added in v0.1.1

func (e *Element) MarshalText() (text []byte, err error)

MarshalText implements encoding/TextMarshaler interface

func (*Element) MultiScalarMult

func (e *Element) MultiScalarMult(s []*Scalar, p []*Element) *Element

MultiScalarMult sets e = sum(s[i] * p[i]), and returns e.

Execution time depends only on the lengths of the two slices, which must match.

func (*Element) Negate

func (e *Element) Negate(p *Element) *Element

Negate sets e = -p, and returns e.

func (*Element) ScalarBaseMult

func (e *Element) ScalarBaseMult(s *Scalar) *Element

ScalarBaseMult sets e = s * B, where B is the canonical generator, and returns e.

func (*Element) ScalarMult

func (e *Element) ScalarMult(s *Scalar, p *Element) *Element

ScalarMult sets e = s * p, and returns e.

func (*Element) String added in v0.1.1

func (e *Element) String() string

String implements the Stringer interface

func (*Element) Subtract

func (e *Element) Subtract(p, q *Element) *Element

Subtract sets e = p - q, and returns e.

func (*Element) UnmarshalText added in v0.1.1

func (e *Element) UnmarshalText(text []byte) error

UnmarshalText implements encoding/TextMarshaler interface

func (*Element) VarTimeDoubleScalarBaseMult

func (e *Element) VarTimeDoubleScalarBaseMult(a *Scalar, A *Element, b *Scalar) *Element

VarTimeDoubleScalarBaseMult sets e = a * A + b * B, where B is the canonical generator, and returns e.

Execution time depends on the inputs.

func (*Element) VarTimeMultiScalarMult

func (e *Element) VarTimeMultiScalarMult(s []*Scalar, p []*Element) *Element

VarTimeMultiScalarMult sets e = sum(s[i] * p[i]), and returns e.

Execution time depends on the inputs.

func (*Element) Zero

func (e *Element) Zero() *Element

Zero sets e to the identity element of the group, and returns e.

type Scalar

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

A Scalar is an element of the ristretto255 scalar field, as specified in draft-hdevalence-cfrg-ristretto-01, Section 3.4. That is, an integer modulo

l = 2^252 + 27742317777372353535851937790883648493

func NewScalar

func NewScalar() *Scalar

NewScalar returns a Scalar set to the value 0.

func (*Scalar) Add

func (s *Scalar) Add(x, y *Scalar) *Scalar

Add sets s = x + y mod l and returns s.

func (*Scalar) Decode

func (s *Scalar) Decode(x []byte) error

Decode sets s = x, where x is a 32 bytes little-endian encoding of s. If x is not a canonical encoding of s, Decode returns an error and the receiver is unchanged.

func (*Scalar) Encode

func (s *Scalar) Encode(b []byte) []byte

Encode appends a 32 bytes little-endian encoding of s to b.

func (*Scalar) Equal

func (s *Scalar) Equal(u *Scalar) int

Equal returns 1 if v and u are equal, and 0 otherwise.

func (*Scalar) FromUniformBytes

func (s *Scalar) FromUniformBytes(x []byte) *Scalar

FromUniformBytes sets s to an uniformly distributed value given 64 uniformly distributed random bytes.

func (*Scalar) Invert

func (s *Scalar) Invert(x *Scalar) *Scalar

Invert sets s = 1 / x such that s * x = 1 mod l and returns s.

If x is 0, the result is undefined.

func (*Scalar) MarshalText added in v0.1.1

func (s *Scalar) MarshalText() (text []byte, err error)

MarshalText implements encoding/TextMarshaler interface

func (*Scalar) Multiply

func (s *Scalar) Multiply(x, y *Scalar) *Scalar

Multiply sets s = x * y mod l and returns s.

func (*Scalar) Negate

func (s *Scalar) Negate(x *Scalar) *Scalar

Negate sets s = -x mod l and returns s.

func (*Scalar) String added in v0.1.1

func (s *Scalar) String() string

String implements the Stringer interface

func (*Scalar) Subtract

func (s *Scalar) Subtract(x, y *Scalar) *Scalar

Subtract sets s = x - y mod l and returns s.

func (*Scalar) UnmarshalText added in v0.1.1

func (s *Scalar) UnmarshalText(text []byte) error

UnmarshalText implements encoding/TextMarshaler interface

func (*Scalar) Zero

func (s *Scalar) Zero() *Scalar

Zero sets s = 0 and returns s.

Directories

Path Synopsis
internal
edwards25519
Package edwards25519 implements group logic for the twisted Edwards curve -x^2 + y^2 = 1 + -(121665/121666)*x^2*y^2 This is better known as the Edwards curve equivalent to curve25519, and is the curve used by the Ed25519 signature scheme.
Package edwards25519 implements group logic for the twisted Edwards curve -x^2 + y^2 = 1 + -(121665/121666)*x^2*y^2 This is better known as the Edwards curve equivalent to curve25519, and is the curve used by the Ed25519 signature scheme.
radix51
GF(2^255-19) field arithmetic in radix 2^51 representation.
GF(2^255-19) field arithmetic in radix 2^51 representation.
scalar
Package scalar implements the ristretto255 scalar group.
Package scalar implements the ristretto255 scalar group.

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