Authentication techniques
Weak: clear-text password
Strong: don’t send secrets on the wire
- One-time password (Eg: S/Key. RFC 2289)
- User remembers secret pass-phrase.
- Server issues a challenge (random #)
- User applies hash function to it multiple times to generate a new password.
- Simple challenge-response: (Eg: CHAP):
- Server encrypts a random number based upon the user’s password (“challenge”)
- User decrypts & returns result (“response”)