csidh

Documentation

Overview

Package csidh implements commutative supersingular isogeny-based Diffie-Hellman key exchange algorithm (CSIDH) resulting from the group action. Implementation uses prime field of a size 512-bits. This implementation is highly experimental work and currently it is not suitable for securing systems.

References:

• cSIDH: ia.cr/2018/383
• Faster cSIDH: ia.cr/2018/782

Index

• Constants
• func DeriveSecret(out *[64]byte, pub *PublicKey, prv *PrivateKey, rng io.Reader) bool
• func GeneratePrivateKey(key *PrivateKey, rng io.Reader) error
• func GeneratePublicKey(pub *PublicKey, prv *PrivateKey, rng io.Reader)
• func Validate(pub *PublicKey, rng io.Reader) bool
• type PrivateKey
  • func (c PrivateKey) Export(out []byte) bool
  • func (c *PrivateKey) Import(key []byte) bool
• type PublicKey
  • func (c *PublicKey) Export(out []byte) bool
  • func (c *PublicKey) Import(key []byte) bool

Constants

const (

	// PrivateKeySize is a size of cSIDH/512 private key in bytes.
	PrivateKeySize = 37
	// PublicKeySize is a size of cSIDH/512 public key in bytes.
	PublicKeySize = 64
	// SharedSecretSize is a size of cSIDH/512 shared secret in bytes.
	SharedSecretSize = 64
)

Functions

func DeriveSecret

func DeriveSecret(out *[64]byte, pub *PublicKey, prv *PrivateKey, rng io.Reader) bool

DeriveSecret computes a cSIDH shared secret. If successful, returns true and fills 'out' with shared secret. Function returns false in case 'pub' is invalid. More precisely, shared secret is a Montgomery coefficient A of a secret curve y^2 = x^3 + Ax^2 + x, computed by applying action of a prv.e on a curve represented by pub.a.

func GeneratePrivateKey

func GeneratePrivateKey(key *PrivateKey, rng io.Reader) error

func GeneratePublicKey

func GeneratePublicKey(pub *PublicKey, prv *PrivateKey, rng io.Reader)

func Validate

func Validate(pub *PublicKey, rng io.Reader) bool

Validate returns true if 'pub' is a valid cSIDH public key, otherwise false. More precisely, the function verifies that curve

y^2 = x^3 + pub.a * x^2 + x

is supersingular.

Types

type PrivateKey

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

Defines operations on private key

func (PrivateKey) Export

func (c PrivateKey) Export(out []byte) bool

func (*PrivateKey) Import

func (c *PrivateKey) Import(key []byte) bool

type PublicKey

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

Defines operations on public key

func (*PublicKey) Export

func (c *PublicKey) Export(out []byte) bool

Assumes key is exported as encoded in Montgomery domain.

func (*PublicKey) Import

func (c *PublicKey) Import(key []byte) bool

Assumes key is in Montgomery domain.