斗 长 Intrusion motive ￥斗 ★★ o Casual prying by non-technical users o Snooping by insiders o Determined attemptto make money o Commercial or militaryespionage
6 Intrusion Motive Casual prying by non-technical users Snooping by insiders Determined attempt to make money Commercial or military espionage
斗 长 Some Example Attacks ￥斗 ★★ o Spoof identity pretend to send a message from your IP address s Man-in-the-middle attack Eavesdrop and delete the original message Insert new message that pretends to be from original sender Replayold messages
7 Some Example Attacks Spoof identity – pretend to send a message from your IP address Man-in-the-middle attack – Eavesdrop and delete the original message – Insert new message that pretends to be from original sender – Replay old messages
斗 长 Security Elements ￥斗 ★★ o Data security not viewed by unauthorized personnel data are not tampered o System security Systems do not do things not supposed to do
8 Security Elements Data security – not viewed by unauthorized personnel – data are not tampered System security – Systems do not do things not supposed to do
斗 长 Security Elements ￥斗 ★★ o Static security Data stored are not compromised Achieved by access control and cryptography o Dynamic security Data in transit is not compromised Achieved by secure communication
9 Security Elements Static security – Data stored are not compromised – Achieved by access control and cryptography Dynamic security – Data in transit is not compromised – Achieved by secure communication
斗 长 Secure communication ￥斗 ★★ o Confidentiali Attacker should not be able to understand data ≈ Authentication: Assure receiver that message is from the right sender s Freshness. Attacker should not be able to replay an old request o Availability No denial-of-service
10 Secure Communication Confidentiality: – Attacker should not be able to understand data Authentication: – Assure receiver that message is from the right sender Freshness: – Attacker should not be able to replay an old request Availability: – No denial-of-service