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_____ _____ encryption is a form of cryptosystem in which encryption and decryption are performed using the same key.

(a)  

The two types of attack on an encryption algorithm are cryptanalysis based on properties of the encryption algorithm, and ____ _____ which involves trying all possible keys.



(a)  

One of the simplest and best-known polyalphabetic ciphers is ____ _____ cipher. In this scheme,
the set of related monoalphabetic substitution rules consists of the 26 Caesar ciphers with shifts of 0 through 25. Each cipher is denoted by a key letter which is the ciphertext letter that substitutes for the plaintext letter a.



(a)  

A ____ ______ cipher processes the input one block of elements at a time producing an output block for each input block whereas a ____ stream ______ cipher processes the input elements continuously producing output one element at a time.



(a)  

The earliest known and simplest use of a substitution cipher was called the (a)   cipher and involved replacing each letter of the alphabet with the letter standing three places further down the alphabet.

The best known multiple letter encryption cipher is the ____ ______ which treats diagrams in the plaintext as single units and translates these units into ciphertext diagrams.

(a)  

A ____ _____ is an encryption/decryption scheme in which a block of plaintext is treated as a whole and used to produce a ciphertext block of equal length.



(a)  

The most widely used encryption scheme is based on the ____ ______ adopted in 1977 by the National Bureau of Standards as Federal Information Processing Standard 46.

 

(a)  

_____ _____ encryption is a form of cryptosystem in which encryption and decryption are
performed using a public key and a private key.

(a)  

Asymmetric encryption transforms plaintext into _____ _____ using one of two keys and an encryption algorithm.



(a)