Refactored all the things!

obfuscated2/frame.go

@@ -9,6 +9,7 @@ import (
 	"github.com/juju/errors"
 
 	"github.com/9seconds/mtg/mtproto"
+	"github.com/9seconds/mtg/utils"
 )
 
 // [frameOffsetFirst:frameOffsetKey:frameOffsetIV:frameOffsetMagic:frameOffsetDC:frameOffsetEnd]
@@ -67,14 +68,7 @@ func (f Frame) ConnectionType() (mtproto.ConnectionType, error) {
 // Invert inverts frame for extracting encryption keys. Pkease check that link:
 // https://blog.susanka.eu/how-telegram-obfuscates-its-mtproto-traffic/
 func (f Frame) Invert() Frame {
-	reversed := make(Frame, FrameLen)
-	copy(reversed, f)
-
-	for i := 0; i < frameLenKey+frameLenIV; i++ {
-		reversed[frameOffsetFirst+i] = f[frameOffsetIV-1-i]
-	}
-
-	return reversed
+	return Frame(utils.ReverseBytes([]byte(f)))
 }
 
 // ExtractFrame extracts exact obfuscated2 handshake frame from given reader.