Asymmetric cryptography (Public-key cryptography)


Concept by Whitfield Diffie and Martin Hellman (1976 IEEE)
A public-key cipher uses a pair of keys 
The two keys are for the same persons (one public, one private)
Security is also in the keys like symmetric cryptography
Issue
Slow
Key size (>1024 bits)
-> Elgamal, RSA (reversibility), ...