1
vote
1answer
100 views

Does the key schedule function need to be a one-way function?

For some key schedule $e_n(e_{n-1}(k))$ (where $e_{n-1}(k)$ is the result of the previous round) , does $e$ need to be a one-way function? In the case of DES or Rijndael the key schedule doesn't ...
8
votes
2answers
658 views

Why does DES use exactly 16 rounds?

Why does DES use exactly 16 rounds and not more or less than 16? What is the significance of using 16 rounds?