Add obfuscated2 server handshake

mtglib/internal/obfuscated2/client_handshake.go

@@ -8,6 +8,33 @@ import (
 	"io"
 )
 
+type clientHandhakeFrame struct {
+	handshakeFrame
+}
+
+func (c *clientHandhakeFrame) decryptor(secret []byte) cipher.Stream {
+	hasher := acquireSha256Hasher()
+	defer releaseSha256Hasher(hasher)
+
+	hasher.Write(c.key()) // nolint: errcheck
+	hasher.Write(secret)  // nolint: errcheck
+
+	return makeAesCtr(hasher.Sum(nil), c.iv())
+}
+
+func (c *clientHandhakeFrame) encryptor(secret []byte) cipher.Stream {
+	arr := clientHandhakeFrame{}
+	invertByteSlices(arr.data[:], c.data[:])
+
+	hasher := acquireSha256Hasher()
+	defer releaseSha256Hasher(hasher)
+
+	hasher.Write(arr.key()) // nolint: errcheck
+	hasher.Write(secret)    // nolint: errcheck
+
+	return makeAesCtr(hasher.Sum(nil), arr.iv())
+}
+
 func ClientHandshake(secret []byte, reader io.Reader) (int, cipher.Stream, cipher.Stream, error) {
 	handshake := clientHandhakeFrame{}