diff --git a/content/notes/23-wireless-mobile.md b/content/notes/23-wireless-mobile.md
index 9fd17ca54..168a79edb 100644
--- a/content/notes/23-wireless-mobile.md
+++ b/content/notes/23-wireless-mobile.md
@@ -4,6 +4,9 @@ aliases:
 tags: 
 - cosc203
 - lecture
+sr-due: 2022-10-23
+sr-interval: 3
+sr-ease: 250
 ---
 
 More wireless phones that wired phones.
diff --git a/content/notes/24-network-security.md b/content/notes/24-network-security.md
new file mode 100644
index 000000000..58e07012b
--- /dev/null
+++ b/content/notes/24-network-security.md
@@ -0,0 +1,40 @@
+---
+title: "24-network-security"
+aliases: 
+tags: 
+- cosc203
+- lecture
+---
+
+# what is it?
+- confidentiality
+	- only sender and reciver should understand message contents
+	- encryption
+- authentication
+	- sender and reciever want to confirm identity of each other
+- message integrity
+	- sender and reciever want to ensure message not altered (in transit, or afterwards) without detection
+- access and availablility
+	- services must be accessible and availble to users
+
+sender and recieves:
+- any king of onnline communication
+
+what can trudy to
+- eavesdrop
+- insert messages into connection
+- impersonation: fake (spoof) source address (or any field)
+- hijacjking "take over" ongoing connection by removing sender or ereciever, inserting himself in place
+- denial of service: prevent others from using a service (e.g., by overloading it)
+
+terminology
+- m: plaintext message
+- 
+
+# Symmetric key crypto
+
+# Public key
+
+# Authentication of devices
+
+# digital signature
diff --git a/content/notes/cosc-203.md b/content/notes/cosc-203.md
index c81c4465a..50f8b0bfe 100644
--- a/content/notes/cosc-203.md
+++ b/content/notes/cosc-203.md
@@ -52,6 +52,7 @@ tags:
 - [21-data link layer and LAN](21-data-link-layer)
 - [22-LAN and physical layer](22-LAN-physical-layer)
 - [23-wireless-mobile](23-wireless-mobile)
+- 
 
 # Archive