ff

README

ff

Finite Field Arithmetic library based on goff (https://github.com/ConsenSys/goff)

Overview

Defines Element interface with the following methods implemented by elements created by goff:

• GetUint64() []uint64
• SetUint64(v uint64) Element
• SetFromArray(x []uint64) Element
• Set(x Element) Element
• SetZero() Element
• SetOne() Element
• Neg(x Element) Element
• Div(x, y Element) Element
• Equal(x Element) bool
• IsZero() bool
• Inverse(x Element) Element
• SetRandom() Element
• One() Element
• Add(x, y Element) Element
• AddAssign(x Element) Element
• Double(x Element) Element
• Sub(x, y Element) Element
• SubAssign(x Element) Element
• Exp(x Element, exponent ...uint64) Element
• FromMont() Element
• ToMont() Element
• ToRegular() Element
• String() string
• ToByte() []byte
• FromByte(x []byte) Element
• ToBigInt(res *big.Int) *big.Int
• ToBigIntRegular(res *big.Int) *big.Int
• SetBigInt(v *big.Int) Element
• SetString(s string) Element
• Legendre() int
• Sqrt(x Element) Element
• Mul(x, y Element) Element
• MulAssign(x Element) Element
• Square(x Element) Element

Adding Additional Elements

To add an additional Element :

go install github.com/iden3/goff
go run goff -m 21888242871839275222246405745257275088548364400416034343698204186575808495617 -o ./ff -p ff -e element_bn256p -i Element

This command will include element_bn256p in directory ./ff implementing intereface Element

Elements defined

Currently, there are two elements defined:

FF_BN256_FQ for field defined by prime 21888242871839275222246405745257275088696311157297823662689037894645226208583

FF_BN256_FP for field defined by prime 21888242871839275222246405745257275088548364400416034343698204186575808495617

Example

el1, err := NewElement(FF_BN256_FP)
el1.SetRandom()
    
el2, err := NewElement(FF_BN256_FP)
el2.SetRandom()

el1.Add(el1, el2)

Documentation

Overview

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Package ff contains field arithmetic operations

Index

• Constants
• func Bit(el Element, b int) int
• func IsValid(elType int) bool
• func Msb(el Element) int
• type Element
  • func FromInterface(i1 interface{}, t int) (Element, error)
  • func NewElement(t int) (Element, error)

Constants

const (
	// 21888242871839275222246405745257275088696311157297823662689037894645226208583
	FF_BN256_FQ = iota
	//21888242871839275222246405745257275088548364400416034343698204186575808495617
	FF_BN256_FP
)

Type of FF defined

const (
	DEFAULT_PRIME = FF_BN256_FP
)

Functions

func Bit

func Bit(el Element, b int) int

Retrieves bit b from Element

func IsValid

func IsValid(elType int) bool

Check if Element belongs to a known type

func Msb

func Msb(el Element) int

Returns number of bits in element

Types

type Element

type Element interface {
	GetUint64() []uint64
	SetUint64(v uint64) Element
	SetFromArray(x []uint64) Element
	Set(x Element) Element
	SetZero() Element
	SetOne() Element
	Neg(x Element) Element
	Div(x, y Element) Element
	Equal(x Element) bool
	IsZero() bool
	Inverse(x Element) Element
	SetRandom() Element
	One() Element
	Add(x, y Element) Element
	AddAssign(x Element) Element
	Double(x Element) Element
	Sub(x, y Element) Element
	SubAssign(x Element) Element
	Exp(x Element, exponent ...uint64) Element
	FromMont() Element
	ToMont() Element
	ToRegular() Element
	String() string
	ToByte() []byte
	FromByte(x []byte) Element
	ToBigInt(res *big.Int) *big.Int
	ToBigIntRegular(res *big.Int) *big.Int
	SetBigInt(v *big.Int) Element
	SetString(s string) Element
	Legendre() int
	Sqrt(x Element) Element
	Mul(x, y Element) Element
	MulAssign(x Element) Element
	Square(x Element) Element
}

interface to describe Finite Field

func FromInterface

func FromInterface(i1 interface{}, t int) (Element, error)

FromInterface converts i1 from uint64, int, string, or element_bn256p, big.Int into element_ panic if provided type is not supported

func NewElement

func NewElement(t int) (Element, error)

Create new Finite Field Element depending on type