Exam 20: Symmetric Encryption and Message Confidentiality

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

For general-purpose stream-oriented transmission you would typically use _______ mode.

__________ 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.

A ________ is a key used between entities for the purpose of distributing session keys.

With _________ encryption the encryption process is carried out at the two end systems.

All encryption algorithms are based on two general principles: substitution and _________.

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

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 three most important symmetric block ciphers are: 3DES, AES, and _____.

The _________ was issued as a federal information-processing standard and is intended to replace DES and 3DES with an algorithm that is more secure and efficient.

_________ is the original message or data that is fed into the algorithm as input.

The National Bureau of Standards is now the National Institute ofStandards and Technology.

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

The exact substitutions and transformations performed by the algorithm depend on the ________.

Cryptographic systems are generically classified by _________.

"The plaintext is 64 bits in length and the key is 56 bits in length;longer plaintext amounts are processed in 64-bit blocks" is a description of the DES algorithm.

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

Stream ciphers are far more common than block ciphers.

AES uses a Feistel structure.

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