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go/_patches/github.com/honeybbq/teamspeak-go/crypto/primitives.go

@@ -0,0 +1,95 @@
+package crypto
+
+import (
+	"crypto/ecdsa"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/sha512"
+	"errors"
+
+	"github.com/oasisprotocol/curve25519-voi/curve"
+	"github.com/oasisprotocol/curve25519-voi/curve/scalar"
+)
+
+var errInvalidKeyLength = errors.New("invalid key length")
+
+const (
+	curve25519KeySize = 32
+	clampMaskLow      = 248
+	clampMaskHigh     = 127
+	clampHighBit      = 64
+	sharedSignBit     = 0x80
+	privateKeyTopMask = 0x7F
+)
+
+func GenerateTemporaryKey() ([]byte, []byte, error) {
+	privateKey := make([]byte, curve25519KeySize)
+	_, err := rand.Read(privateKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	ClampScalar(privateKey)
+	sc, err := scalar.NewFromBits(privateKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	publicKey, err := curve.NewEdwardsPoint().MulBasepoint(curve.ED25519_BASEPOINT_TABLE, sc).MarshalBinary()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return publicKey, privateKey, nil
+}
+
+func Sign(priv *ecdsa.PrivateKey, data []byte) ([]byte, error) {
+	hash := sha256.Sum256(data)
+
+	return ecdsa.SignASN1(rand.Reader, priv, hash[:])
+}
+
+func VerifySign(pub *ecdsa.PublicKey, data, sig []byte) bool {
+	hash := sha256.Sum256(data)
+
+	return ecdsa.VerifyASN1(pub, hash[:], sig)
+}
+
+func ClampScalar(key []byte) {
+	if len(key) < curve25519KeySize {
+		return
+	}
+	key[0] &= clampMaskLow
+	key[curve25519KeySize-1] &= clampMaskHigh
+	key[curve25519KeySize-1] |= clampHighBit
+}
+
+func GetSharedSecret2(publicKey, privateKey []byte) ([]byte, error) {
+	if len(publicKey) != curve25519KeySize || len(privateKey) != curve25519KeySize {
+		return nil, errInvalidKeyLength
+	}
+
+	privateKeyCpy := make([]byte, curve25519KeySize)
+	copy(privateKeyCpy, privateKey)
+	privateKeyCpy[curve25519KeySize-1] &= privateKeyTopMask
+	sc, err := scalar.NewFromBits(privateKeyCpy)
+	if err != nil {
+		return nil, err
+	}
+
+	pub := curve.NewEdwardsPoint()
+	err = pub.UnmarshalBinary(publicKey)
+	if err != nil {
+		return nil, err
+	}
+	pub.Neg(pub)
+
+	sharedPoint := curve.NewEdwardsPoint().Mul(pub, sc)
+	shared, err := sharedPoint.MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	shared[curve25519KeySize-1] ^= sharedSignBit
+
+	hash := sha512.Sum512(shared)
+
+	return hash[:], nil
+}