Decrypt the message "KIE LML MJ" that was encrypted with the affine cipher with the function f(p)=(21.p) mod 26. Hint 1: First find the inverse of 21 modulo 26, å. Then solve the linear congruences for each letter. For example, for K (encoded as 10) solve ā.10= a.21.x (mod 26). Hint 2: Find the encoding of letters below. ABCDEFGHIJK |LMNO PQRS IUVW x | Y Z 0 12 34 56 789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Decrypt the message "KIE LML MJ" that was encrypted with the affine cipher with the function f(p)=(21.p) mod 26. Hint 1: First find the inverse of 21 modulo 26, å. Then solve the linear congruences for each letter. For example, for K (encoded as 10) solve ā.10= a.21.x (mod 26). Hint 2: Find the encoding of letters below. ABCDEFGHIJK |LMNO PQRS IUVW x | Y Z 0 12 34 56 789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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An animal name has been encoded using the letter to number correspondence abcde t 8hij k 1 m nop qrstuVH x y z e 1 2 3 4 5 6 7 8 9 18 11 12 13 14 15 16 17 18 19 28 21 22 23 24 25 and the encryption function e :n + (n + 2) mod 26 The result is the secret identification kiwcpc . What is the animal? The answer will be a nonsense word (no numbers).
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Let a block cipher with secret key K be chained in the following way: Cj = Mi-1 0 E((M¡ O Cj-1), K) for i>0 where Mo and Co are fixed public initialization vectors, K is the secret key known to both transmitter and receiver, and E and D represent encryption and decryption, respectively. Q1) Determine the equation for decryption. Q2) Suppose that ciphertext C3 is damaged in transmission. Which plaintext blocks become undecipherable as a result? Explain.
that the ciphertexts are C = 0xbcc61793955b5eb5 and C2 = 0xdea2c2 fd718d3b77. We also happen to know that M1 A cryptography student has accidentally used the same keystream to encrypt two different messages, M1 and M2. We know Оx805d3а2029c0а386. a) What is M2 in hexadecimal? Please give your answer a leading 0x and use lowercase letters only. b) What is the keystream? Please give your answer a leading Ox and use lowercase letters only. Hint: These are all 8 byte numbers and will fit in an unsigned long type on most systems.
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A cryptanalyst has determined that the three most common trigraphs in a ciphertext are LME, WRI, and ZYC, and guesses that these ciphertext trigraphs correspond to the three most common trigraphs in English text, THE, AND, and THA. If the plaintext was encrypted using a Hill trigraphic cipher described by C ≡ AP (mod 26), what are the entries of the 3 × 3 encrypting matrix A?
To prevent the tapping and use of information on a wireless network which has brought untold mistrust amongst the directors of Okonko Systems, you suggested that every message that is transmitted should go through the following: A systematic two left bit shift; After “a” above, the algorithm f[(6m +2) + k] mode 13 should be applied to the cipher text, where m is the message and k =9 is a key; After “b” above, perform a systematic right bit shift to the new cipher; The message should then be transmitted. If on a trial basis, the message is “genomics” Use the mono – alphabetic letters where a = 0, b = 1, ….z = 25 to find the cipher that would be transmitted
An animal name has been encoded using the letter to number correspondence abc de f 8hijk 1 m nopP arstu vH x y z e 1 2 3 4 5 6 7 8 9 1e 11 12 13 14 15 16 17 18 19 28 21 22 23 24 25 and the encryption function e:n + (n + 2) mod 26 The result is the secret identification kiwcpc . What is the animal? The answer will be a nonsense word (no numbers).
Suppose Professor Chao's public key is (n, e) = (923, 37). Send him a message (m = 23) encrypted by RSA. What is the ciphertext and suppose you intercept an RSA encrypted message (c = 148) sent to Professor Chao then Decrypt the message and what is the original plaintext? Calculate the modular exponentiation and modular multiplicative inverse
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based on advanced encryption standard (AES) if the shared key is "AWDFGNJKLQCERRYB" AND THE IBPUT of mix-column of round 3 is "EYTRRWQYKJMGFDAA" . Find the second byte of mix-column of the same round
Consider a very simple symmetric block encryption algorithm in which 32-bits blocks of plaintext are encrypted using a 64-bit key. Encryption is defined as C = (PK₁) K₁ where C = ciphertext, K = secret key, Ko = leftmost 64 bits of K, K₁ = rightmost 64 bits of K,+ = bitwise exclusive OR, and is addition mod 264. a. Show the decryption equation. That is, show the equation for P as a function of C, Ko, and K₁. b. Suppose and adversary has access to two sets of plaintexts and their correspond- ing ciphertexts and wishes to determine K. We have the two equations: C = (PK) K₁; C = (PK) K₁ First, derive an equation in one unknown (e.g., Ko). Is it possible to proceed fur- ther to solve for Ko?