elgamal

package
v0.8.2 Latest Latest
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 Go to latest Published: Jun 11, 2019 License: AGPL-3.0 Imports: 8 Imported by: 0

Documentation

Overview

Package elgamal provides primitives required by the ElGamal encryption scheme. It's based on Python's implementation: https://github.com/asonnino/coconut/blob/master/coconut/utils.py.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrUnmarshalLength represents an error thrown during unmarshal when the byte arrays have unexpected lengths.
	ErrUnmarshalLength = errors.New("the byte array provided is incomplete")
)

Functions

func Decrypt 

func Decrypt(g *bpgroup.BpGroup, pk *PrivateKey, enc *Encryption) *Curve.ECP

Decrypt takes the ElGamal encryption of a message and returns a point on the G1 curve that represents original h^m.

func Keygen 

func Keygen(g *bpgroup.BpGroup) (*PrivateKey, *PublicKey)

Keygen generates private and public keys required for ElGamal encryption scheme. Passing coconut.Params as an argument would cause issues with cyclic dependencies, passing BpGroup in that case is sufficient.

func ValidateKeyPair 

func ValidateKeyPair(pk *PrivateKey, pub *PublicKey) bool

ValidateKeyPair checks if the ElGamal keypair was correctly formed.

Types

type Encryption 

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

Encryption are the two points on the G1 curve that represent encryption of message in form of h^m.

func Encrypt 

func Encrypt(g *bpgroup.BpGroup, pub *PublicKey, m *Curve.BIG, h *Curve.ECP) (*Encryption, *Curve.BIG)

Encrypt encrypts the given message in the form of h^m, where h is a point on the G1 curve using the given public key. The random k is returned alongside the encryption as it is required by the Coconut Scheme to create proofs of knowledge.

func NewEncryptionFromPoints 

func NewEncryptionFromPoints(c1 *Curve.ECP, c2 *Curve.ECP) *Encryption

NewEncryptionFromPoints wraps two points on G1 curve as ElGamal Encryption.

func (*Encryption) C1 

func (e *Encryption) C1() *Curve.ECP

C1 returns first group element of the ElGamal Encryption.

func (*Encryption) C2 

func (e *Encryption) C2() *Curve.ECP

C2 returns second group element of the ElGamal Encryption.

func (*Encryption) FromProto 

func (e *Encryption) FromProto(pe *ProtoEncryption) error

FromProto takes a protobuf representation of the object and unmarshals its attributes.

func (*Encryption) MarshalBinary 

func (e *Encryption) MarshalBinary() ([]byte, error)

MarshalBinary is an implementation of a method on the BinaryMarshaler interface defined in https://golang.org/pkg/encoding/

func (*Encryption) ToProto 

func (e *Encryption) ToProto() (*ProtoEncryption, error)

ToProto creates a protobuf representation of the object.

func (*Encryption) UnmarshalBinary 

func (e *Encryption) UnmarshalBinary(data []byte) error

UnmarshalBinary is an implementation of a method on the BinaryUnmarshaler interface defined in https://golang.org/pkg/encoding/

func (*Encryption) Validate 

func (e *Encryption) Validate() bool

Validate checks for nil elements in the encryption.

type EncryptionResult 

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

EncryptionResult encapsulates entire result of ElGamal encryption, including random k.

func NewEncryptionResult 

func NewEncryptionResult(enc *Encryption, k *Curve.BIG) *EncryptionResult

NewEncryptionResult returns new instance of EncryptionResult from provided encryption and k.

func (*EncryptionResult) Enc 

func (er *EncryptionResult) Enc() *Encryption

Enc returns encryption part of the EncryptionResult.

func (*EncryptionResult) K 

func (er *EncryptionResult) K() *Curve.BIG

K returns random k part of the EncryptionResult.

type PrivateKey 

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

PrivateKey represents an ElGamal private key.

func NewPrivateKey 

func NewPrivateKey(d *Curve.BIG) *PrivateKey

NewPrivateKey returns new instance of ElGamal private key with the provided argument.

func (*PrivateKey) D 

func (pk *PrivateKey) D() *Curve.BIG

D returns the appropriate part of the ElGamal private key.

func (*PrivateKey) FromPEMFile 

func (pk *PrivateKey) FromPEMFile(f string) error

FromPEMFile reads out the secret key from a PEM file at path f.

func (*PrivateKey) FromProto 

func (pk *PrivateKey) FromProto(ppk *ProtoPrivateKey) error

FromProto takes a protobuf representation of the object and unmarshals its attributes.

func (*PrivateKey) MarshalBinary 

func (pk *PrivateKey) MarshalBinary() ([]byte, error)

MarshalBinary is an implementation of a method on the BinaryMarshaler interface defined in https://golang.org/pkg/encoding/

func (*PrivateKey) ToPEMFile 

func (pk *PrivateKey) ToPEMFile(f string) error

ToPEMFile writes out the secret key to a PEM file at path f.

func (*PrivateKey) ToProto 

func (pk *PrivateKey) ToProto() (*ProtoPrivateKey, error)

ToProto creates a protobuf representation of the object.

func (*PrivateKey) UnmarshalBinary 

func (pk *PrivateKey) UnmarshalBinary(data []byte) error

UnmarshalBinary is an implementation of a method on the BinaryUnmarshaler interface defined in https://golang.org/pkg/encoding/

func (*PrivateKey) Validate 

func (pk *PrivateKey) Validate() bool

Validate checks for nil elements in the key.

type ProtoEncryption 

type ProtoEncryption struct {
	C1                   []byte   `protobuf:"bytes,1,opt,name=C1,json=c1,proto3" json:"C1,omitempty"`
	C2                   []byte   `protobuf:"bytes,2,opt,name=C2,json=c2,proto3" json:"C2,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

func (*ProtoEncryption) Descriptor 

func (*ProtoEncryption) Descriptor() ([]byte, []int)

func (*ProtoEncryption) GetC1 

func (m *ProtoEncryption) GetC1() []byte

func (*ProtoEncryption) GetC2 

func (m *ProtoEncryption) GetC2() []byte

func (*ProtoEncryption) ProtoMessage 

func (*ProtoEncryption) ProtoMessage()

func (*ProtoEncryption) Reset 

func (m *ProtoEncryption) Reset()

func (*ProtoEncryption) String 

func (m *ProtoEncryption) String() string

func (*ProtoEncryption) XXX_DiscardUnknown 

func (m *ProtoEncryption) XXX_DiscardUnknown()

func (*ProtoEncryption) XXX_Marshal 

func (m *ProtoEncryption) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ProtoEncryption) XXX_Merge 

func (m *ProtoEncryption) XXX_Merge(src proto.Message)

func (*ProtoEncryption) XXX_Size 

func (m *ProtoEncryption) XXX_Size() int

func (*ProtoEncryption) XXX_Unmarshal 

func (m *ProtoEncryption) XXX_Unmarshal(b []byte) error

type ProtoPrivateKey 

type ProtoPrivateKey struct {
	D                    []byte   `protobuf:"bytes,1,opt,name=D,json=d,proto3" json:"D,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

just to keep it consistent when/if writing to a PEM file

func (*ProtoPrivateKey) Descriptor 

func (*ProtoPrivateKey) Descriptor() ([]byte, []int)

func (*ProtoPrivateKey) GetD 

func (m *ProtoPrivateKey) GetD() []byte

func (*ProtoPrivateKey) ProtoMessage 

func (*ProtoPrivateKey) ProtoMessage()

func (*ProtoPrivateKey) Reset 

func (m *ProtoPrivateKey) Reset()

func (*ProtoPrivateKey) String 

func (m *ProtoPrivateKey) String() string

func (*ProtoPrivateKey) XXX_DiscardUnknown 

func (m *ProtoPrivateKey) XXX_DiscardUnknown()

func (*ProtoPrivateKey) XXX_Marshal 

func (m *ProtoPrivateKey) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ProtoPrivateKey) XXX_Merge 

func (m *ProtoPrivateKey) XXX_Merge(src proto.Message)

func (*ProtoPrivateKey) XXX_Size 

func (m *ProtoPrivateKey) XXX_Size() int

func (*ProtoPrivateKey) XXX_Unmarshal 

func (m *ProtoPrivateKey) XXX_Unmarshal(b []byte) error

type ProtoPublicKey 

type ProtoPublicKey struct {
	P                    []byte   `protobuf:"bytes,1,opt,name=P,json=p,proto3" json:"P,omitempty"`
	G                    []byte   `protobuf:"bytes,2,opt,name=G,json=g,proto3" json:"G,omitempty"`
	Gamma                []byte   `protobuf:"bytes,3,opt,name=Gamma,json=gamma,proto3" json:"Gamma,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

func (*ProtoPublicKey) Descriptor 

func (*ProtoPublicKey) Descriptor() ([]byte, []int)

func (*ProtoPublicKey) GetG 

func (m *ProtoPublicKey) GetG() []byte

func (*ProtoPublicKey) GetGamma 

func (m *ProtoPublicKey) GetGamma() []byte

func (*ProtoPublicKey) GetP 

func (m *ProtoPublicKey) GetP() []byte

func (*ProtoPublicKey) ProtoMessage 

func (*ProtoPublicKey) ProtoMessage()

func (*ProtoPublicKey) Reset 

func (m *ProtoPublicKey) Reset()

func (*ProtoPublicKey) String 

func (m *ProtoPublicKey) String() string

func (*ProtoPublicKey) XXX_DiscardUnknown 

func (m *ProtoPublicKey) XXX_DiscardUnknown()

func (*ProtoPublicKey) XXX_Marshal 

func (m *ProtoPublicKey) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ProtoPublicKey) XXX_Merge 

func (m *ProtoPublicKey) XXX_Merge(src proto.Message)

func (*ProtoPublicKey) XXX_Size 

func (m *ProtoPublicKey) XXX_Size() int

func (*ProtoPublicKey) XXX_Unmarshal 

func (m *ProtoPublicKey) XXX_Unmarshal(b []byte) error

type PublicKey 

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

PublicKey represents an ElGamal public key.

func NewPublicKey 

func NewPublicKey(p *Curve.BIG, g *Curve.ECP, gamma *Curve.ECP) *PublicKey

NewPublicKey returns new instance of ElGamal public key with the provided arguments.

func PublicKeyFromPrivate 

func PublicKeyFromPrivate(pk *PrivateKey) *PublicKey

PublicKeyFromPrivate returns a public key instance corresponding to the provided private key.

func (*PublicKey) FromPEMFile 

func (pub *PublicKey) FromPEMFile(f string) error

FromPEMFile reads out the secret key from a PEM file at path f.

func (*PublicKey) FromProto 

func (pub *PublicKey) FromProto(ppub *ProtoPublicKey) error

FromProto takes a protobuf representation of the object and unmarshals its attributes.

func (*PublicKey) G 

func (pub *PublicKey) G() *Curve.ECP

G returns the appropriate part of the ElGamal public key.

func (*PublicKey) Gamma 

func (pub *PublicKey) Gamma() *Curve.ECP

Gamma returns the appropriate part of the ElGamal public key.

func (*PublicKey) MarshalBinary 

func (pub *PublicKey) MarshalBinary() ([]byte, error)

MarshalBinary is an implementation of a method on the BinaryMarshaler interface defined in https://golang.org/pkg/encoding/

func (*PublicKey) P 

func (pub *PublicKey) P() *Curve.BIG

P returns the appropriate part of the ElGamal public key.

func (*PublicKey) ToPEMFile 

func (pub *PublicKey) ToPEMFile(f string) error

ToPEMFile writes out the verification key to a PEM file at path f.

func (*PublicKey) ToProto 

func (pub *PublicKey) ToProto() (*ProtoPublicKey, error)

ToProto creates a protobuf representation of the object.

func (*PublicKey) UnmarshalBinary 

func (pub *PublicKey) UnmarshalBinary(data []byte) error

UnmarshalBinary is an implementation of a method on the BinaryUnmarshaler interface defined in https://golang.org/pkg/encoding/

func (*PublicKey) Validate 

func (pub *PublicKey) Validate() bool

Validate checks for nil elements in the key.

Source Files

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