The BasicsClassical CiphersThe Caesar CipherThe Vigenère CipherHow Ciphers WorkThe PermutationThe Mode of OperationWhy Classical Ciphers Are InsecureThe Perfect Cipher: The One-Time PadEncryption and DecryptionWhy Is the One-Time Pad Secure?Encryption SecurityAttack ModelsSecurity GoalsSecurity NotionsAsymmetric EncryptionWhen Ciphers Do More Than EncryptionAuthenticated EncryptionFormat-Preserving EncryptionFully Homomorphic EncryptionSearchable EncryptionTweakable EncryptionHow Things Can Go WrongWeak CipherWrong ModelFurther Reading