Explanation/Reference:
Explanation:
It is false that both block size and key length can be extended to multiples of 64 bits; they can be extended in multiples of 32 bits.
Rijndael is a block symmetric cipher that was chosen to fulfill the Advanced Encryption Standard. It uses a
128-bit block size and various key lengths (128, 192, 256).
The Rijndael specification is specified with block and key sizes that may be any multiple of 32 bits, both with a minimum of 128 and a maximum of 256 bits.
Incorrect Answers:
A: It is true that the design of Rijndael was strongly influenced by the design of the block cipher Square.
B: It is true that a total of 25 combinations of key length and block length are possible.
D: It is true that the cipher has a variable block length and key length.
References:
http://searchsecurity.techtarget.com/definition/Rijndael
https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
Krutz, Ronald L. and Russel Dean Vines, The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, New York, 2001, p. 145