diff --git a/key_storage.ino b/key_storage.ino
new file mode 100644
index 0000000..e7c0eaf
--- /dev/null
+++ b/key_storage.ino
@@ -0,0 +1,48 @@
+#include "USB.h"
+#include "USBMSC.h"
+#include "FS.h"
+#include "FFat.h"
+#include "WiFi.h"
+#include "esp_bt.h"  
+
+USBMSC MSC;
+
+#define DISK_SIZE (100 * 1024) 
+
+typedef int32_t i32;
+typedef uint32_t u32;
+typedef uint8_t u8;
+
+
+u8 msc_disk[DISK_SIZE];
+
+i32 onRead(u32 lba, u32 offset, void* buffer, u32 bufsize) {
+    u8* dst = (u8*)buffer;
+    memcpy(dst, msc_disk + offset, bufsize);
+    return bufsize;
+}
+
+i32 onWrite(u32 lba, u32 offset, u8* buffer, u32 bufsize) {
+    memcpy(msc_disk + offset, buffer, bufsize);
+    return bufsize;
+}
+
+void setup() {
+    Serial.begin(115200);
+
+    WiFi.mode(WIFI_OFF);
+    btStop(); 
+
+    MSC.vendorID("XIAO");
+    MSC.productID("USB Drive");
+    MSC.onRead(onRead);
+    MSC.onWrite(onWrite);
+    MSC.mediaPresent(true);
+    MSC.begin(DISK_SIZE/512, 512);
+    
+    USB.begin();
+}
+
+void loop() {
+    delay(1000);
+}
\ No newline at end of file
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..9a1dca2
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,12 @@
+setup
+
+nix-shell -p arduino-cli 
+
+arduino-cli config add board_manager.additional_urls https://files.seeedstudio.com/arduino/package_seeeduino_boards_index.json
+arduino-cli core update-index
+arduino-cli core install Seeeduino:esp32
+
+arduino-cli lib install "MSC"
+
+arduino-cli compile --fqbn esp32:esp32:esp32s3 key_storage.ino 
+arduino-cli upload -p /dev/ttyACM0 --fqbn esp32:esp32:esp32s3 key_storage.ino