The definition of a Shift Cipher can be expressed as follows: Def. Let x, y, k ∈ Z26 with the encryption operation as ek(x) ≡ x + k mod 26 and the decryption operation as dk(y) ≡ y - k mod 26. Given the provided letter encoding, what would be the encoding of the plaintext word ATTACK after applying a shift cipher with a k=17?

The definition of a Shift Cipher can be expressed as follows: Def. Let x, y, k ∈ Z26 with the encryption operation as ek(x) ≡ x + k mod 26 and the decryption operation as dk(y) ≡ y - k mod 26. Given the provided letter encoding, what would be the encoding of the plaintext word ATTACK after applying a shift cipher with a k=17?

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 affine cipher has the form c = (am+b) mod n. Suppose m is an integer between 0 and 25, eachinteger representing a letter.(a) Let n = 26, a = 3, and b = 123. What is the ciphertext corresponding to the phrase THIS IS A CIPHERMESSAGE.(b) A requirement for a cipher is that every plaintext letter correspond to a different ciphertext letter. If either aand b is not relatively prime to n, does the affine cipher meet this property? Either prove it does or presenta counterexample.
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