Integrity vs.Secrecy Integrity:attacker cannot change message without being detected Encryption:attacker cannot read message correctly without key -Note:encryption does not guarantee integrity. Reason:attacker can change ciphertext arbitrarily and any ciphertext can be decrypted to get the corresponding plaintext(although possibly garbage). M network Alice Bob Learns M-attack on secrecy Changes M-attack on integrity 22 Integrity vs. Secrecy  Integrity: attacker cannot change message without being detected  Encryption: attacker cannot read message correctly without key ─ Note: encryption does not guarantee integrity. ─ Reason: attacker can change ciphertext arbitrarily and any ciphertext can be decrypted to get the corresponding plaintext (although possibly garbage). network Learns M – attack on secrecy Alice Bob M M Changes M – attack on integrity M’