Outline

The building blocks of cryptography
Secrecy: symmetric and public-key encryption
Integrity: cryptographic hashes
Authenticity: message authentication codes and digital signatures

The uses of cryptography
Secrecy applications
Encrypted email
SSL
Encrypted file storage
Privacy applications
Private access to email and the Internet
Private credentials
Private electronic cash
Steganography

The limitations of cryptography
The problems cryptography can't solve for you