Small refactorings

mtglib/internal/obfuscated2/utils.go

@@ -0,0 +1,23 @@
+package obfuscated2
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+)
+
+func makeAesCtr(key, iv []byte) cipher.Stream {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+
+	return cipher.NewCTR(block, iv)
+}
+
+func invertByteSlices(dst, src []byte) {
+	lenDst := len(dst) - 1
+
+	for i, v := range src {
+		dst[lenDst-i] = v
+	}
+}