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Question;9. An encryption;scheme is __________ secure if the ciphertext generated by the scheme does not;contain enough information to determine uniquely the corresponding plaintext;no matter how much ciphertext is available.;10. The earliest known and simplest use of a substitution;cipher was called the __________ cipher and involved replacing each letter of;the alphabet with the letter standing three places further down the alphabet.;11. The best known multiple letter encryption cipher is the;which treats digrams in the plaintext as single units and translates these;units into ciphertext digrams.;12. The task of making large quantities of random keys on a;regular basis and distributing a key of equal length to both sender and receiver;for every message sent are difficulties of the __________ scheme.;13. The simplest;transposition cipher is the _________ technique in which the plaintext is written;down as a sequence of diagonals and then read off as a sequence of rows.;14. The most widely;used cipher ever is the __________.;15. The;consist of a set of independently rotating cylinders through which;electrical pulses can flow. Each cylinder has 26 input pins;and 26 output pins with internal wiring that connects each input pin to a;unique output pin.


Paper#55159 | Written in 18-Jul-2015

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