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+---
+title: "25-network-security-2"
+aliases: 
+tags: 
+- cosc203
+- lecture
+---
+
+
+# TLS
+- security protocol above transport layer.
+	- supported by most browsers
+	- prvides, confidentaility, integrity, authentication
+- replaced SSL
+
+- provides API that any application can use
+- ![http view of TLS](https://i.imgur.com/c68ksNH.png)
+- QUIC and http3: moves transpor tlayer functions to app layer, on top of UDP
+
+how
+- handshake: use certificates, private keys to authenticate each other, exchange or create shared secret
+- key derivation: use shared secret to derive set of keys
+- data transfer: as a series of records, not just one time transactions
+- connection closure: special message to close message
+
+
+protocols
+- handshake protocol
+- changechipherspec protocol
+	- choose encryption algerithms
+- alert Protocol
+	- terminate
+	- error reporting
+- record protocol
+	- divide data to segments
+	- encrypt and authenticate and send
+
+handshake
+- ![](https://i.imgur.com/ROiKXo9.png)
+
+cryptographic keys
+- bad to use the same key for more than one crytographic algorithm (encryption and authentication)
+- uses master secret
+- ![](https://i.imgur.com/ZBiTZsk.png)
+
+
+# IPSec
+
+# firewall
+
+# IDS
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