Symmetric and Asymmetric cryptography

• Symmetric cyphers
  • One secret key used for encryption and decryption
  • Secret key must be known by both sender and receiver
  • Key transfer problem
  • Fast to encrypt/decrypt
  • DES, IDEA, ElGamel
• Asymmetric cyphers
  • One key used to encryption, another key used to unencrypt
  • Allows public key architecture - one key is public and freely distributed
  • Slow to encrypt/decrypt
  • RSA, DSA