January 8, 2002
Practical Aspects of Modern Cryptography
Diffie-Hellman Key Exchange
•
What does Eve see?
•
Y
,
Y
a
,
Y
b
•
… but the exchanged key is
Y
ab
.
•
Belief:
Given
Y
,
Y
a
,
Y
b
it is difficult to
compute
Y
ab
.
•
Contrast with discrete logarithm assumption:
Given
Y
,
Y
a
it is difficult to compute
a
.
•
