diff --git a/.vscode/extensions.json b/.vscode/extensions.json
new file mode 100644
index 00000000..f3863412
--- /dev/null
+++ b/.vscode/extensions.json
@@ -0,0 +1,5 @@
+{
+    "recommendations": [
+        "tomoki1207.pdf"
+    ]
+}
\ No newline at end of file
diff --git a/Programming/BSS/stunel/BSS-Stunnel.pdf b/Programming/BSS/stunel/BSS-Stunnel.pdf
new file mode 100644
index 00000000..1e70ba71
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