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 Go to latest Published: Jun 13, 2019 License: GPL-3.0 Imports: 16 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

View Source 
const (
	SALT_SIZE           = 32
	DEFAULT_SCRYPT_COST = 20
	SYMMETRIC_KEY_SIZE  = 128
	NONCE_SIZE          = 64
)

Variables

This section is empty.

Functions

func DefaultCurve 

func DefaultCurve() *openssl.Curve

func DeriveKeyFromPassword 

func DeriveKeyFromPassword(password []byte, salt []byte) []byte

* Derives a symmetric encryption key from a pair of password and salt. It uses Scrypt by default.

func ExpectedBytesLength 

func ExpectedBytesLength(curve *openssl.Curve)

func NewDerivedKey 

func NewDerivedKey(password []byte, salt []byte) ([]byte, error)

* Derives a symmetric encryption key from a pair of password and salt. WARNING: RFC7914 recommends that you use a 2^20 cost value for sensitive files. It is NOT recommended to change the `_scrypt_cost` value unless you know what you are doing.

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.

func SetDefaultCurve 

func SetDefaultCurve(curve *openssl.Curve) error

func UnwrapKey 

func UnwrapKey(wrappedKey []byte, wrappingKey []byte, password []byte, nonce *[24]byte) []byte

* Unwraps a key using a provided wrapping key. Alternatively, it can derive the wrapping key from a password.

TODO can nonce be null? if so, delete that from params

func WrapKey 

func WrapKey(keyToWrap []byte, wrappingKey []byte, password []byte, nonce *[24]byte) []byte

* Wraps a key using a provided wrapping key. Alternatively, it can derive the wrapping key from a password.

TODO look at pyUmbral keys function and nacl.secretbox python implementation, can nonce be null? if so, delete that from params

Types

type Config 

type Config struct {
	Curve  *openssl.Curve
	Params *UmbralParameters
}

TODO pointer params so they can be nil

func NewConfig 

func NewConfig(curve openssl.Curve, params UmbralParameters) Config

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 UmbralKeyingMaterial 

type UmbralKeyingMaterial struct {
	KeyingMaterial []byte
}

* This type with its methods handles keying material for Umbral, by allowing deterministic derivation of UmbralPrivateKeys based on labels. Don't use this key material directly as a key.

func KeyingMaterialFromBytes 

func KeyingMaterialFromBytes(keyBytes []byte, wrappingKey []byte, password []byte, nonce *[24]byte) UmbralKeyingMaterial

func NewUmbralKeyingMaterial 

func NewUmbralKeyingMaterial(keyingMaterial *[]byte) UmbralKeyingMaterial

func (UmbralKeyingMaterial) DerivePrivKeyByLabel 

func (uKeyMat UmbralKeyingMaterial) DerivePrivKeyByLabel(label []byte, salt []byte, params *UmbralParameters) UmbralPrivateKey

func (UmbralKeyingMaterial) ToBytes 

func (uKeyMat UmbralKeyingMaterial) ToBytes(wrappingKey []byte, password []byte, nonce *[24]byte) []byte

type UmbralParameters 

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

func DefaultParams 

func DefaultParams() *UmbralParameters

func NewUmbralParameters 

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

func (*UmbralParameters) Equals 

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

type UmbralPrivateKey 

type UmbralPrivateKey struct {
	Params    UmbralParameters
	BnKey     ModBigNum
	PublicKey UmbralPublicKey
}

func GenerateUmbralPrivateKey 

func GenerateUmbralPrivateKey(params *UmbralParameters) UmbralPrivateKey

Generates a private key and returns it.

func PrivateKeyFromBytes 

func PrivateKeyFromBytes(keyBytes []byte, wrappingKey *[]byte, password *[]byte, params *UmbralParameters, nonce *[24]byte) UmbralPrivateKey

Loads an Umbral private key from bytes. Optionally, uses a wrapping key to unwrap an encrypted Umbral private key. Alternatively, if a password is provided it will derive the wrapping key from it.

func (UmbralPrivateKey) GetPublicKey 

func (uPrivKey UmbralPrivateKey) GetPublicKey() UmbralPublicKey

func (UmbralPrivateKey) ToBytes 

func (uPrivKey UmbralPrivateKey) ToBytes(wrappingKey *[]byte, password *[]byte, nonce *[24]byte) []byte

Returns an UmbralPrivateKey as bytes with optional symmetric encryption via nacl's Salsa20-Poly1305. If a password is provided instead of a wrapping key, it will use Scrypt for key derivation.

func (UmbralPrivateKey) ToCryptographyPrivKey 

func (uPrivKey UmbralPrivateKey) ToCryptographyPrivKey() ecdsa.PrivateKey

type UmbralPublicKey 

type UmbralPublicKey struct {
	PointKey Point
	Params   UmbralParameters
}

func FromHex 

func FromHex(hexUmbralPubKey string, isCompressed bool) UmbralPublicKey

func PublicKeyFromBytes 

func PublicKeyFromBytes(keyBytes []byte, params *UmbralParameters) UmbralPublicKey

* Loads an Umbral public key from bytes.

func (UmbralPublicKey) ByteString 

func (uPubKey UmbralPublicKey) ByteString() ([]byte, error)

func (UmbralPublicKey) Equals 

func (uPubKey UmbralPublicKey) Equals(umbralPubKey UmbralPublicKey) bool

func (UmbralPublicKey) ExpectedBytesLength 

func (uPubKey UmbralPublicKey) ExpectedBytesLength(curve *openssl.Curve, isCompressed bool) uint

* Returns the size (in bytes) of an UmbralPublicKey given a curve. If no curve is provided, it uses the default curve. By default, it assumes compressed representation (is_compressed = True).

func (UmbralPublicKey) Hash 

func (uPubKey UmbralPublicKey) Hash() int

func (UmbralPublicKey) ToBytes 

func (uPubKey UmbralPublicKey) ToBytes(isCompressed bool) []byte

* Returns an Umbral public key as bytes.

func (UmbralPublicKey) ToHex 

func (uPubKey UmbralPublicKey) ToHex(isCompressed bool) string

Source Files

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