Update

.gitignore

@@ -12,3 +12,4 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+.idea/

README.md

@@ -1,11 +1,28 @@
 # gxor
-gxor程序根据输入的二进制文件进行异或运算输出
+
+**gxor** 程序根据输入的二进制文件进行异或运算输出
 
 ```
 [gxor] Xor Binary file
 
-Usage : 
+Usage : gxor -input-file payload.bin -output-file out.bin -xor-key 10 -appendFlag A
+```
+
 
-gxor -input-file payload.bin -output-file out.bin -xor-key 10
+## 使用帮助
 
 ```
+Usage of ./gxor:
+  -append-flag string
+    	flag for file head, 1 bytes (default "A")
+  -input-file string
+    	input bin file
+  -output-file string
+    	input bin file (default "output.bin")
+  -xor-key int
+    	input xor key (default 8)
+```
+
+- append-flag 主要是为了防止直接异或过的shellcode代码被查杀，因此可以在文件头添加一些字符串
+
+

gxor.go

@@ -11,7 +11,7 @@ var (
 	inputBinaryFile  = flag.String("input-file", "", "input bin file")
 	xorKey           = flag.Int("xor-key", 8, "input xor key")
 	outputBinaryFile = flag.String("output-file", "output.bin", "input bin file")
-	appendFlag = flag.String("append-flag", "A", "flag for file head, 1 bytes")
+	appendFlag = flag.String("append-flag", "", "flag for file head, 1 bytes")
 )
 
 func usage() {
@@ -48,7 +48,10 @@ func main() {
 		fmt.Println(err)
 		return
 	}
-	newFile.Write([]byte(*appendFlag))
+
+	if len(*appendFlag) > 0 {
+		newFile.Write([]byte(*appendFlag))
+	}
 	newFile.Write(data)
 	fmt.Println("[*]Flag Size:", len(*appendFlag))
 	fmt.Println("[*]Output:", *outputBinaryFile)