Exam 20: Symmetric Encryption and Message Confidentiality

______ mode is typically used for a general-purpose block-oriented transmission and is useful for high-speed requirements.

AES uses a Feistel structure.

One desirable property of a stream cipher is that the ciphertext be of the same length as the plaintext.

The most powerful,and most common,approach to countering the threats to network security is ________.

Symmetric encryption is also referred to as secret-key or single-key encryption.

A symmetric encryption scheme has five ingredients: plaintext,encryption algorithm,ciphertext,decryption algorithm and _________.

__________ is a term that refers to the means of delivering a key to two parties that wish to exchange data without allowing others to see the key.

"Each block of 64 plaintext bits is encoded independently using the same key" is a description of the CBC mode of operation.

For symmetric encryption to work the two parties to an exchange must share the same _____,which must be protected from access by others.

For stream-oriented transmission over noisy channel you would typically use _______ mode.

An encryption scheme is _________ if the cost of breaking the cipher exceeds the value of the encrypted information and/or the time required to break the cipher exceeds the useful lifetime of the information.

Unlike ECB and CBC modes,________ mode requires only the implementation of the encryption algorithm and not the decryption algorithm.

Cryptographic systems are generically classified by _________.

There are _____ modes of operation defined by NIST that are intended to cover virtually all the possible applications of encryption for which a block cipher could be used.

The most widely used encryption scheme is based on the _________ adopted in 1977 by the National Bureau of Standards.

With ______ encryption each vulnerable communications link is equipped on both ends with an encryption device.

One disadvantage of the link encryption approach is that the message must be decrypted each time it enters a frame switch.

If the analyst is able to get the source system to insert into the system a message chosen by the analyst,then a ________ attack is possible.

_________ is the process of attempting to discover the plaintext or key.

Key distribution can be achieved for two parties A and B by a third party selecting the key and physically delivering it to A and B.