Exam Name___________________________________ TRUE/FALSE. Write ’T’ if the statement is true and ’F’ if the statement is false. 1) With the introduction of the computer the need for automated tools for protecting files and other information stored on the computer became evident. 2) There is a natural tendency on the part of users and system managers to perceive little benefit from security investment until a security failure occurs. 3) There are clear boundaries between network security and internet
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x y z S C J A X U F B Q K T P R W E Z H V L I G Y D N M O Table 1.11: Simple substitution encryption table (a) Encrypt the plaintext message The gold is hidden in the garden. (b) Make a decryption table‚ that is‚ make a table in which the ciphertext alphabet is in order from A to Z and the plaintext alphabet is mixed up. (c) Use your decryption table from (b) to decrypt the following message. IBXLX JVXIZ SLLDE VAQLL DEVAU QLB Exercise 3 Each of the following messages has been encrypted
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A preliminary version of this paper appears in the proceedings of Eurocrypt 2013. This is the full version. Message-Locked Encryption and Secure Deduplication Mihir Bellare1 Sriram Keelveedhi2 Thomas Ristenpart3 March 2013 Abstract We formalize a new cryptographic primitive‚ Message-Locked Encryption (MLE)‚ where the key under which encryption and decryption are performed is itself derived from the message. MLE provides a way to achieve secure deduplication (space-efficient secure outsourced
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agreements (SLAs) figure prominently? Selected Answer: Remote Access Correct Answer: WAN • Question 6 0.5 out of 0.5 points What is ciphertext? Selected Answer: The opposite of cleartext. Data sent as ciphertext is not visible and not decipherable. Correct Answer: The opposite of cleartext. Data sent as ciphertext is not visible and not decipherable. • Question 7 0.5 out of 0.5 points What term refers to ensuring the latest software revisions‚
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Question 1 0 out of 3.704 points Public-key encryption is based on a ____. Selected Answer: d. key Answers: a. message authentication code (MAC) b. certificate c. hash value d. key Question 2 3.704 out of 3.704 points Which symmetric encryption cryptosystems was developed to replace both DES and 3DES? Selected Answer: b. AES Answers: a. WEP b. AES c. DES d. RSA Question 3 3.704 out of 3.704 points Hash ____ are mathematical functions that create a hash
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What is the difference between a block cipher and a stream cipher? 2. What is the difference between a monoalphabetic cipher and a polyalphabetic cipher? 3. A ciphertext has been generated with an affine cipher. The most frequent letter of the ciphertext is ’B’‚ and the second most frequent letter of the ciphertext is ’U’. Break this code. 4. When the PT-109 American patrol boat‚ under the command of Lieutenant John F. Kennedy‚ was sunk by a Japanese destroyer‚ a message was received
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SOLUTIONS MANUAL CRYPTOGRAPHY AND NETWORK SECURITY PRINCIPLES AND PRACTICE FOURTH EDITION WILLIAM STALLINGS Copyright 2006: William Stallings -2- © 2006 by William Stallings All rights reserved. No part of this document may be reproduced‚ in any form or by any means‚ or posted on the Internet‚ without permission in writing from the author. -3- NOTICE This manual contains solutions to all of the review questions and homework problems in Cryptography and Network Security‚
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There is an error in the following ciphertext representation of this quote‚ what is it? What should the correct ciphertext be? (Hint: when using the CrypTool there are several ways to decode one that you can use is “Playfair” encipher option‚ the plaintext and key provided in the lab information‚ and DESELECTING the “separate duplicate letters only within pairs” option) SDAHFOWGRABSSRERIVBYBSCIMQTFNIVETGHBSNQCNCSDTDHBSNQCD ECNICIFCTIC The error is the ciphertext included additional alphabets located
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(10+10 =20 Marks) 2. Explain RC4 algorithm. Encrypt the Message “HI” using RC4 algorithm‚ with four states and 2 bit key values are [2‚5] ASCII value for H – 1001000I – 1001001 (5+5=10 Marks) 3. a. Find the plaintext from the ciphertext using cesar cipher – VSRQJHEREVTXDUHSDQWU b. Encipher “CHUCK NORRIS IS A TOUGH GUY” using a rail fence cipher. c. Decipher “JYENR BOALR ERIIE LOLAR ISNDE TLYRC ACIFB PE” using a simple 4 column transposition
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the full 16 round DES in less than the complexity of exhaustive search. The d a t a analysis phase computes the key by analyzing about 2% ciphertexts in 237time. The 2% usable ciphertexts are obtained during the data collection phase from a larger pool of 247 chosen plaintexts by a simple bit repetition criteria which discards more than 99.9% of the ciphertexts as soon as they are generated. While earlier versions of differential attacks were based on huge counter arrays‚ the new attack requires negligible
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