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key exchange refactoring

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Sun Yimin 2022-06-23 10:24:10 +08:00 committed by GitHub
parent 461f4b6838
commit b4b9cd07d9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 34 additions and 33 deletions
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55
sm2/sm2_keyexchange.go
View File

@ -10,12 +10,6 @@ import (
"github.com/emmansun/gmsm/sm3"
)
// Point represent point on curve
type Point struct {
X *big.Int
Y *big.Int
}
// KeyExchange key exchange struct, include internal stat in whole key exchange flow.
// Initiator's flow will be: NewKeyExchange -> InitKeyExchange -> transmission -> ConfirmResponder
// Responder's flow will be: NewKeyExchange -> waiting ... -> RepondKeyExchange -> transmission -> ConfirmInitiator
@ -26,17 +20,17 @@ type KeyExchange struct {
z []byte // owner identifiable id
peerPub *ecdsa.PublicKey // peer public key
peerZ []byte // peer identifiable id
r *big.Int // random which will be used to compute secret
secret Point // generated secret which will be passed to peer
peerSecret Point // received peer's secret
w2 *big.Int // internal state which will be used when compute the key and signature
w2Minus1 *big.Int // internal state which will be used when compute the key and signature
v Point // internal state which will be used when compute the key and signature
key []byte // key will be used after key agreement
r *big.Int // Ephemeral Private Key, random which will be used to compute secret
secret *ecdsa.PublicKey // Ephemeral Public Key, generated secret which will be passed to peer
peerSecret *ecdsa.PublicKey // received peer's secret, Ephemeral Public Key
w2 *big.Int // internal state which will be used when compute the key and signature, 2^w
w2Minus1 *big.Int // internal state which will be used when compute the key and signature, 2^w – 1
v *ecdsa.PublicKey // internal state which will be used when compute the key and signature, u/v
key []byte // shared key will be used after key agreement
}
// GetKey return key after key agreement
func (ke *KeyExchange) GetKey() []byte {
// GetSharedKey return shared key after key agreement
func (ke *KeyExchange) GetSharedKey() []byte {
return ke.key
}
@ -62,6 +56,13 @@ func NewKeyExchange(priv *PrivateKey, peerPub *ecdsa.PublicKey, uid, peerUID []b
if err != nil {
return nil, err
}
ke.secret = &ecdsa.PublicKey{}
ke.secret.Curve = priv.PublicKey.Curve
ke.peerSecret = &ecdsa.PublicKey{}
ke.peerSecret.Curve = peerPub.Curve
ke.v = &ecdsa.PublicKey{}
ke.v.Curve = priv.PublicKey.Curve
return
}
@ -71,13 +72,13 @@ func initKeyExchange(ke *KeyExchange, r *big.Int) {
}
// InitKeyExchange generate random with responder uid, for initiator's step A1-A3
func (ke *KeyExchange) InitKeyExchange(rand io.Reader) (*Point, error) {
func (ke *KeyExchange) InitKeyExchange(rand io.Reader) (*ecdsa.PublicKey, error) {
r, err := randFieldElement(ke.privateKey, rand)
if err != nil {
return nil, err
}
initKeyExchange(ke, r)
return &ke.secret, nil
return ke.secret, nil
}
func (ke *KeyExchange) sign(isResponder bool, prefix byte) []byte {
@ -107,7 +108,7 @@ func (ke *KeyExchange) sign(isResponder bool, prefix byte) []byte {
return hash.Sum(nil)
}
func (ke *KeyExchange) generateKey(isResponder bool) {
func (ke *KeyExchange) generateSharedKey(isResponder bool) {
var buffer []byte
buffer = append(buffer, toBytes(ke.privateKey, ke.v.X)...)
buffer = append(buffer, toBytes(ke.privateKey, ke.v.Y)...)
@ -122,7 +123,7 @@ func (ke *KeyExchange) generateKey(isResponder bool) {
ke.key = key
}
func respondKeyExchange(ke *KeyExchange, r *big.Int, rA *Point) (*Point, []byte, error) {
func respondKeyExchange(ke *KeyExchange, r *big.Int, rA *ecdsa.PublicKey) (*ecdsa.PublicKey, []byte, error) {
ke.secret.X, ke.secret.Y = ke.privateKey.ScalarBaseMult(r.Bytes())
ke.r = r
// Calculate tB
@ -142,21 +143,21 @@ func respondKeyExchange(ke *KeyExchange, r *big.Int, rA *Point) (*Point, []byte,
return nil, nil, errors.New("sm2: key exchange fail")
}
ke.generateKey(true)
ke.generateSharedKey(true)
if !ke.genSignature {
return &ke.secret, nil, nil
return ke.secret, nil, nil
}
return &ke.secret, ke.sign(true, 0x02), nil
return ke.secret, ke.sign(true, 0x02), nil
}
// RepondKeyExchange when responder receive rA, for responder's step B1-B8
func (ke *KeyExchange) RepondKeyExchange(rand io.Reader, rA *Point) (*Point, []byte, error) {
func (ke *KeyExchange) RepondKeyExchange(rand io.Reader, rA *ecdsa.PublicKey) (*ecdsa.PublicKey, []byte, error) {
if !ke.privateKey.IsOnCurve(rA.X, rA.Y) {
return nil, nil, errors.New("sm2: received invalid random from initiator")
}
ke.peerSecret = *rA
ke.peerSecret = rA
r, err := randFieldElement(ke.privateKey, rand)
if err != nil {
return nil, nil, err
@ -165,11 +166,11 @@ func (ke *KeyExchange) RepondKeyExchange(rand io.Reader, rA *Point) (*Point, []b
}
// ConfirmResponder for initiator's step A4-A10
func (ke *KeyExchange) ConfirmResponder(rB *Point, sB []byte) ([]byte, error) {
func (ke *KeyExchange) ConfirmResponder(rB *ecdsa.PublicKey, sB []byte) ([]byte, error) {
if !ke.privateKey.IsOnCurve(rB.X, rB.Y) {
return nil, errors.New("sm2: received invalid random from responder")
}
ke.peerSecret = *rB
ke.peerSecret = rB
// Calcualte tA
t := (&big.Int{}).And(ke.w2Minus1, ke.secret.X)
t.Add(ke.w2, t)
@ -187,7 +188,7 @@ func (ke *KeyExchange) ConfirmResponder(rB *Point, sB []byte) ([]byte, error) {
if ke.v.X.Sign() == 0 && ke.v.Y.Sign() == 0 {
return nil, errors.New("sm2: key exchange fail")
}
ke.generateKey(false)
ke.generateSharedKey(false)
if len(sB) > 0 {
buffer := ke.sign(false, 0x02)
if goSubtle.ConstantTimeCompare(buffer, sB) != 1 {

12
sm9/sm9.go
View File

@ -511,7 +511,7 @@ type KeyExchange struct {
g1 *bn256.GT // internal state which will be used when compute the key and signature
g2 *bn256.GT // internal state which will be used when compute the key and signature
g3 *bn256.GT // internal state which will be used when compute the key and signature
key []byte // key will be used after key agreement
key []byte // shared key will be used after key agreement
}
// NewKeyExchange create one new KeyExchange object
@ -525,8 +525,8 @@ func NewKeyExchange(priv *EncryptPrivateKey, uid, peerUID []byte, keyLen int, ge
return ke
}
// GetKey return key after key agreement
func (ke *KeyExchange) GetKey() []byte {
// GetSharedKey return key after key agreement
func (ke *KeyExchange) GetSharedKey() []byte {
return ke.key
}
@ -571,7 +571,7 @@ func (ke *KeyExchange) sign(isResponder bool, prefix byte) []byte {
return hash.Sum(nil)
}
func (ke *KeyExchange) generateKey(isResponder bool) {
func (ke *KeyExchange) generateSharedKey(isResponder bool) {
var buffer []byte
if isResponder {
buffer = append(buffer, ke.peerUID...)
@ -607,7 +607,7 @@ func respondKeyExchange(ke *KeyExchange, hid byte, r *big.Int, rA *bn256.G1) (*b
ke.g3.ScalarMult(ke.g1, r)
ke.g2 = ke.privateKey.EncryptMasterPublicKey.ScalarBaseMult(r)
ke.generateKey(true)
ke.generateSharedKey(true)
if !ke.genSignature {
return ke.secret, nil, nil
@ -643,7 +643,7 @@ func (ke *KeyExchange) ConfirmResponder(rB *bn256.G1, sB []byte) ([]byte, error)
return nil, errors.New("sm9: verify responder's signature fail")
}
}
ke.generateKey(false)
ke.generateSharedKey(false)
return ke.sign(false, 0x83), nil
}