diff --git a/data/.gitignore b/data/.gitignore
new file mode 100644
index 0000000..3f82532
--- /dev/null
+++ b/data/.gitignore
@@ -0,0 +1,11 @@
+.DS_Store
+.idea
+*.log
+tmp/
+
+*.py[cod]
+*.egg
+build
+htmlcov
+
+*.pem
diff --git a/demo/config.py.simple b/demo/config.py.simple
index 7d17154..9316321 100644
--- a/demo/config.py.simple
+++ b/demo/config.py.simple
@@ -1,4 +1,8 @@
 "Store App settings"
+from pathlib import Path
+
+_ROOT_DIR = Path().parent.resolve()
+KEY_PATH = _ROOT_DIR / "data" / "key.pem"
 
 USER_AGENT = "COSCUP-demo"
 AP_CONTENT_TYPE = "application/activity+json"
diff --git a/demo/utils/key.py b/demo/utils/key.py
new file mode 100644
index 0000000..c04124b
--- /dev/null
+++ b/demo/utils/key.py
@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+"""process Key."""
+
+import sys
+
+from pathlib import Path
+from Crypto.PublicKey import RSA
+from demo.config import KEY_PATH
+
+
+def get_pubkey_as_pem(key_path: Path) -> str:
+    """Exporting public key from private key file."""
+    text = key_path.read_text()
+    return RSA.import_key(text).public_key().export_key("PEM").decode("utf-8")
+
+
+def gen_key():
+    """Generate key."""
+    if KEY_PATH.exists():
+        print("is existing!")
+        sys.exit(2)
+    else:
+        k = RSA.generate(2048)
+        privkey_pem = k.exportKey("PEM").decode("utf-8")
+        KEY_PATH.write_text(privkey_pem)