keys.go

package noise

import (
	"encoding/hex"
	"encoding/json"
	"github.com/oasislabs/ed25519"
	"io"
)

const (
	// SizePublicKey is the size in bytes of a nodes/peers public key.
	SizePublicKey = ed25519.PublicKeySize

	// SizePrivateKey is the size in bytes of a nodes/peers private key.
	SizePrivateKey = ed25519.PrivateKeySize
)

type (
	// PublicKey is the default node/peer public key type.
	PublicKey [SizePublicKey]byte

	// PrivateKey is the default node/peer private key type.
	PrivateKey [SizePrivateKey]byte
)

var (
	// ZeroPublicKey is the zero-value for a node/peer public key.
	ZeroPublicKey PublicKey

	// ZeroPrivateKey is the zero-value for a node/peer private key.
	ZeroPrivateKey PrivateKey
)

// GenerateKeys randomly generates a new pair of cryptographic keys. Nil may be passed to rand in order to use
// crypto/rand by default. It throws an error if rand is invalid.
func GenerateKeys(rand io.Reader) (publicKey PublicKey, privateKey PrivateKey, err error) {
	pub, priv, err := ed25519.GenerateKey(rand)
	if err != nil {
		return publicKey, privateKey, err
	}

	copy(publicKey[:], pub)
	copy(privateKey[:], priv)

	return publicKey, privateKey, nil
}

// Verify returns true if the cryptographic signature of data is representative of this public key.
func (k PublicKey) Verify(data, signature []byte) bool {
	return ed25519.Verify(k[:], data, signature)
}

// String returns the hexadecimal representation of this public key.
func (k PublicKey) String() string {
	return hex.EncodeToString(k[:])
}

// MarshalJSON returns the hexadecimal representation of this public key in JSON. It should never throw an error.
func (k PublicKey) MarshalJSON() ([]byte, error) {
	return json.Marshal(k.String())
}

// Sign uses this private key to sign data and return its cryptographic signature as a slice of bytes.
func (k PrivateKey) Sign(data []byte) []byte {
	return ed25519.Sign(k[:], data)
}

// String returns the hexadecimal representation of this private key.
func (k PrivateKey) String() string {
	return hex.EncodeToString(k[:])
}

// MarshalJSON returns the hexadecimal representation of this private key in JSON. It should never throw an error.
func (k PrivateKey) MarshalJSON() ([]byte, error) {
	return json.Marshal(hex.EncodeToString(k[:]))
}

// Public returns the public key associated to this private key.
func (k PrivateKey) Public() PublicKey {
	var publicKey PublicKey
	copy(publicKey[:], (ed25519.PrivateKey)(k[:]).Public().(ed25519.PublicKey))

	return publicKey
}