Exam 12: Message Authentication Codes

A CTR-based authenticated encryption approach is the most efficient mode of operation for high-speed packet networks.

Message authentication is a mechanism or service used to verify the integrity of a message.

The MAC does not provide a digital signature because both sender and receiver share the same key.

A __________ takes a variable length message and a secret key as input and produces an authentication code.

The HtE approach is used in the __________ protocol to protect WiFi networks.

The types of functions that may be used to produce an authenticator are grouped into three classes: hash function,message authentication code,and ___________ .

The GCM mode makes use of two functions: __________,which is a keyed hash function,and GCTR.

The security of any MAC function based on an embedded hash function depends in some way on the cryptographic strength of the underlying hash function.

___________ is a term used to describe encryption systems that simultaneously protect confidentiality and authenticity of communications.

The __________ mode of operation was standardized by NIST specifically to support the security requirements of IEEE 802.1 WiFi wireless local area networks but can be used in any networking application requiring authenticated encryption.

With _________ authentication an opponent would have difficulty generating ciphertext that when decrypted would have valid error control bits.

The key algorithmic ingredients of _________ are the AES encryption algorithm,the CTR mode of operation,and the CMAC authentication algorithm.

To attack MD5,the attacker can choose any set of messages and work on these offline on a dedicated computing facility to find a collision.

Insertion of messages into the network from a fraudulent source is a __________ attack.

The order in which the frame check sequence and encryption functions are performed is not critical for authentication.

A brute-force attack on a MAC is easier than a brute-force attack on a hash function.

_________ encryption provides authentication among those who share the secret key.

One means of forming a MAC is to combine a cryptographic hash function in some fashion with a secret key.

The __________ algorithm can be defined as using the cipher block chaining mode of operation of DES with an initialization vector of zero.

One approach to constructing a MAC is to use a symmetric block cipher in such a way that it produces a __________ output for a variable length input.