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 Go to latest Published: Sep 13, 2018 License: GPL-3.0 Imports: 6 Imported by: 0

Documentation

Overview

Copyright (C) 2018 NuCypher

This file is part of goUmbral.

goUmbral is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

goUmbral is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with goUmbral. If not, see <https://www.gnu.org/licenses/>.

Copyright (C) 2018 NuCypher

This file is part of goUmbral.

goUmbral is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

goUmbral is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with goUmbral. If not, see <https://www.gnu.org/licenses/>.

Copyright (C) 2018 NuCypher

This file is part of goUmbral.

goUmbral is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

goUmbral is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with goUmbral. If not, see <https://www.gnu.org/licenses/>.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ExpectedBytesLength 

func ExpectedBytesLength(curve *openssl.Curve)

func PointLength 

func PointLength(curve *openssl.Curve, isCompressed bool) uint

Returns the size (in bytes) of a compressed Point given a curve. If no curve is provided, it returns 0.

Types

type ModBigNum 

type ModBigNum struct {
	Bignum openssl.BigNum
	Curve  *openssl.Curve
}

func BytesToModBN 

func BytesToModBN(data []byte, curve *openssl.Curve) (*ModBigNum, error)

Returns the ModBigNum associated with the bytes-converted bignum provided by the data argument.

func GenRandModBN 

func GenRandModBN(curve *openssl.Curve) (*ModBigNum, error)

Returns a ModBigNum with a cryptographically secure OpenSSL BIGNUM based on the given curve.

func HashToModBN 

func HashToModBN(bytes []byte, params *UmbralParameters) (*ModBigNum, error)

Returns a ModBigNum based on provided data hashed by blake2b.

func IntToModBN 

func IntToModBN(num int, curve *openssl.Curve) (*ModBigNum, error)

func NewModBigNum 

func NewModBigNum(cNum openssl.BigNum, curve *openssl.Curve) (*ModBigNum, error)

func (*ModBigNum) Add 

func (z *ModBigNum) Add(x, y *ModBigNum) error

ModBigNum.Add() will perform (x + y) modulo the order of the curve of x and y. It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Add will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Bytes 

func (m *ModBigNum) Bytes() ([]byte, error)

func (ModBigNum) Compare 

func (m ModBigNum) Compare(other *ModBigNum) int

func (*ModBigNum) Copy 

func (m *ModBigNum) Copy() (*ModBigNum, error)

func (*ModBigNum) Div 

func (z *ModBigNum) Div(x, y *ModBigNum) error

ModBigNum.Div() will perform (x / y) modulo the order of the curve of x and y. It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Div will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Equals 

func (m *ModBigNum) Equals(other *ModBigNum) bool

func (*ModBigNum) Free 

func (m *ModBigNum) Free()

func (*ModBigNum) Invert 

func (z *ModBigNum) Invert(x *ModBigNum) error

ModBigNum.Invert() computes (x*z)%m==1 where m is the order of the curve of x and z. It will then set z to the result of that operation.

x and z must use the same curve and must be initialized.

Invert will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Mod 

func (z *ModBigNum) Mod(x, y *ModBigNum) error

ModBigNum.Mod() will perform (x % y). It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Mod will return the error, and nil otherwise.

func (*ModBigNum) Mul 

func (z *ModBigNum) Mul(x, y *ModBigNum) error

ModBigNum.Mul() will perform (x * y) modulo the order of the curve of x and y. It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Mul will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Neg 

func (z *ModBigNum) Neg(x *ModBigNum) error

ModBigNum.Neg() computes the modular opposite (i. e., additive inverse) of x. It will then set z to the result of that operation.

x and z must use the same curve and must be initialized.

Neg will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Pow 

func (z *ModBigNum) Pow(x, y *ModBigNum) error

ModBigNum.Pow() will perform (x^y) modulo the order of the curve of x and y. It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Pow will return the error if one occurred, and nil otherwise.

func (*ModBigNum) Sub 

func (z *ModBigNum) Sub(x, y *ModBigNum) error

ModBigNum.Sub() will perform (x - y) modulo the order of the curve of x and y. It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Sub will return the error if one occurred, and nil otherwise.

type Point 

type Point struct {
	ECPoint openssl.ECPoint
	Curve   *openssl.Curve
}

func AffineToPoint 

func AffineToPoint(affineX, affineY *big.Int, curve *openssl.Curve) (*Point, error)

Returns a Point object from the given affine coordinates.

func BytesToPoint 

func BytesToPoint(data []byte, curve *openssl.Curve) (*Point, error)

func GenRandPoint 

func GenRandPoint(curve *openssl.Curve) (*Point, error)

Returns a Point struct with a cryptographically secure EC_POINT based on the provided curve.

This operation isn't safe unless you know the discrete log of the generated Point.

func GetGeneratorFromCurve 

func GetGeneratorFromCurve(curve *openssl.Curve) *Point

func NewPoint 

func NewPoint(point openssl.ECPoint, curve *openssl.Curve) (*Point, error)

Generate a new Point struct based on the arguments provided.

If point is nil then GetNewPoint will generate a new opensslraphically secure ECPoint and check for errors before returning the new Point.

if point is nil AND the curve group is also nil then GetNewPoint will fail and return the error.

func UnsafeHashToPoint 

func UnsafeHashToPoint(data []byte, params *UmbralParameters, label []byte) (*Point, error)

WARNING: Do not use when the input data is secret, as this implementation is not in constant time, and hence, it is not safe with respect to timing attacks. TODO: Check how to uniformly generate ycoords. Currently, it only outputs points where ycoord is even (i.e., starting with 0x02 in compressed notation)

func (*Point) Add 

func (z *Point) Add(x, y *Point) error

Point.Add() will perform (x + y). It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Add will return the error if one occurred, and nil otherwise.

func (*Point) Copy 

func (m *Point) Copy() (*Point, error)

func (*Point) Equals 

func (m *Point) Equals(other *Point) (bool, error)

func (*Point) Free 

func (m *Point) Free()

func (*Point) Invert 

func (z *Point) Invert(x *Point) error

Point.Invert() will find the inverse of x. It will then set z to the result of that operation.

x must be initialized.

Invert will return the error if one occurred, and nil otherwise.

func (*Point) Mul 

func (z *Point) Mul(x *Point, y *ModBigNum) error

Point.Mul() will perform (x * y). It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Mul will return the error if one occurred, and nil otherwise.

func (*Point) Sub 

func (z *Point) Sub(x, y *Point) error

Point.Sub() will perform (x - y). It will then set z to the result of that operation.

x, y, and z must use the same curve and must be initialized.

Sub will return the error if one occurred, and nil otherwise.

func (Point) ToAffine 

func (m Point) ToAffine() (*big.Int, *big.Int, error)

Returns an x and y coordinate of the Point as a Go big.Int.

func (Point) ToBytes 

func (m Point) ToBytes(isCompressed bool) ([]byte, error)

Returns the Point serialized as bytes. It will return a compressed form if isCompressed is set to True.

type UmbralParameters 

type UmbralParameters struct {
	Curve *openssl.Curve
	Size  uint
	G     *Point
	U     *Point
}

func NewUmbralParameters 

func NewUmbralParameters(curve *openssl.Curve) (*UmbralParameters, error)

func (*UmbralParameters) Equals 

func (m *UmbralParameters) Equals(other *UmbralParameters) bool

Source Files

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