mirror of
https://github.com/cheat/cheat.git
synced 2024-11-28 00:36:53 +01:00
112 lines
3.4 KiB
Go
112 lines
3.4 KiB
Go
// Package ecc implements a generic interface for ECDH, ECDSA, and EdDSA.
|
|
package ecc
|
|
|
|
import (
|
|
"crypto/subtle"
|
|
"io"
|
|
|
|
"github.com/ProtonMail/go-crypto/openpgp/errors"
|
|
ed448lib "github.com/cloudflare/circl/sign/ed448"
|
|
)
|
|
|
|
type ed448 struct{}
|
|
|
|
func NewEd448() *ed448 {
|
|
return &ed448{}
|
|
}
|
|
|
|
func (c *ed448) GetCurveName() string {
|
|
return "ed448"
|
|
}
|
|
|
|
// MarshalBytePoint encodes the public point from native format, adding the prefix.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.5.5.5
|
|
func (c *ed448) MarshalBytePoint(x []byte) []byte {
|
|
// Return prefixed
|
|
return append([]byte{0x40}, x...)
|
|
}
|
|
|
|
// UnmarshalBytePoint decodes a point from prefixed format to native.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.5.5.5
|
|
func (c *ed448) UnmarshalBytePoint(point []byte) (x []byte) {
|
|
if len(point) != ed448lib.PublicKeySize+1 {
|
|
return nil
|
|
}
|
|
|
|
// Strip prefix
|
|
return point[1:]
|
|
}
|
|
|
|
// MarshalByteSecret encoded a scalar from native format to prefixed.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.5.5.5
|
|
func (c *ed448) MarshalByteSecret(d []byte) []byte {
|
|
// Return prefixed
|
|
return append([]byte{0x40}, d...)
|
|
}
|
|
|
|
// UnmarshalByteSecret decodes a scalar from prefixed format to native.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.5.5.5
|
|
func (c *ed448) UnmarshalByteSecret(s []byte) (d []byte) {
|
|
// Check prefixed size
|
|
if len(s) != ed448lib.SeedSize+1 {
|
|
return nil
|
|
}
|
|
|
|
// Strip prefix
|
|
return s[1:]
|
|
}
|
|
|
|
// MarshalSignature splits a signature in R and S, where R is in prefixed native format and
|
|
// S is an MPI with value zero.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.2.3.3.2
|
|
func (c *ed448) MarshalSignature(sig []byte) (r, s []byte) {
|
|
return append([]byte{0x40}, sig...), []byte{}
|
|
}
|
|
|
|
// UnmarshalSignature decodes R and S in the native format. Only R is used, in prefixed native format.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-5.2.3.3.2
|
|
func (c *ed448) UnmarshalSignature(r, s []byte) (sig []byte) {
|
|
if len(r) != ed448lib.SignatureSize+1 {
|
|
return nil
|
|
}
|
|
|
|
return r[1:]
|
|
}
|
|
|
|
func (c *ed448) GenerateEdDSA(rand io.Reader) (pub, priv []byte, err error) {
|
|
pk, sk, err := ed448lib.GenerateKey(rand)
|
|
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
return pk, sk[:ed448lib.SeedSize], nil
|
|
}
|
|
|
|
func getEd448Sk(publicKey, privateKey []byte) ed448lib.PrivateKey {
|
|
return append(privateKey, publicKey...)
|
|
}
|
|
|
|
func (c *ed448) Sign(publicKey, privateKey, message []byte) (sig []byte, err error) {
|
|
// Ed448 is used with the empty string as a context string.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-13.7
|
|
sig = ed448lib.Sign(getEd448Sk(publicKey, privateKey), message, "")
|
|
|
|
return sig, nil
|
|
}
|
|
|
|
func (c *ed448) Verify(publicKey, message, sig []byte) bool {
|
|
// Ed448 is used with the empty string as a context string.
|
|
// See https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-crypto-refresh-06#section-13.7
|
|
return ed448lib.Verify(publicKey, message, sig, "")
|
|
}
|
|
|
|
func (c *ed448) ValidateEdDSA(publicKey, privateKey []byte) (err error) {
|
|
priv := getEd448Sk(publicKey, privateKey)
|
|
expectedPriv := ed448lib.NewKeyFromSeed(priv.Seed())
|
|
if subtle.ConstantTimeCompare(priv, expectedPriv) == 0 {
|
|
return errors.KeyInvalidError("ecc: invalid ed448 secret")
|
|
}
|
|
return nil
|
|
}
|