<Dd> K and K are independent, and K = K. Sometimes known as 2TDEA or double - length keys . </Dd> <Dd> This provides a shorter key length of 112 bits and a reasonable compromise between DES and Keying option 1, with the same caveat as above . This is an improvement over "double DES" which only requires 2 steps to attack . NIST has deprecated this option . </Dd> <Dt> Keying option 3 </Dt> <Dd> All three keys are identical, i.e. K = K = K . </Dd>

Which of the following is the size of the block for triple des