Chapter 6 - AES question and answers graded A+ 2023/2024

Chapter 6 - AESAES uses a Feistel structure. - correct answer false At each horizontal point, State is the same for both encryption and decryption. - correct answer true DES is a block cipher intended to replace AES for commercial applications. - correct answer false The nonlinearity of the S-box is due to the use of the multiplicative inverse. - correct answer true Virtually all encryption algorithms, both conventional and public-key, involve arithmetic operations on integers. - correct answer true Compared to public-key ciphers such as RSA, the structure of AES and most symmetric ciphers is quite complex and cannot be explained as easily as many other cryptographic algorithms. - correct answer true InvSubBytes is the inverse of ShiftRows. - correct answer false The ordering of bytes within a matrix is by column. - correct answer true In the Advanced Encryption Standard the decryption algorithm is identical to the encryption algorithm. - correct answer false The S-box is designed to be resistant to known cryptanalytic attacks. - correct answer true As with any block cipher, AES can be used to construct a message authentication code, and for this, only decryption is used. - correct answer false The inverse add round key transformation is identical to the forward add round key transformation because the XOR operation is its own inverse. - correct answer true The Rijndael developers designed the expansion key algorithm to be resistant to known cryptanalytic attacks. - correct answer true The transformations AddRoundKey and InvMixColumn alter the sequence of bytes in State. - correct answer false AES can be implemented very efficiently on an 8-bit processor. - correct answer true The Advanced Encryption Standard was published by the __________ in 2001. - correct answer NIST In Advanced Encryption Standard all operations are performed on __________ bytes. - correct answer 8-bit The AES cipher begins and ends with a(n) _________ stage because any other stage, applied at the beginning or end, is reversible without knowledge of the key and would add no security. - correct answer AddRoundKey A __________ is a set in which you can do addition, subtraction, multiplication and division without leaving the set. - correct answer field Division requires that each nonzero element have a(n) __________ inverse. - correct answer multiplicative In AES, the arithmetic operations of addition, multiplication and division are performed over the finite field _________ . - correct answer GF(2^8) In the AES structure both encryption and decryption ciphers begin with a(n) __________ stage, followed by nine rounds that each include all four stages, followed by a tenth round of three stages. - correct answer AddRoundKey