4. El-Gamal O Consider the El-Gamal encryption scheme and let p = 19 and 9 = 3 (a) Suppose the private key is x = 7. Compute the public key y. (b) Encrypt the message M = 8 using the public key above and r = 8. (c) Verify your calculation in part (b) above by decrypting the ciphertext you obtained in part (b)

4. El-Gamal O Consider the El-Gamal encryption scheme and let p = 19 and 9 = 3 (a) Suppose the private key is x = 7. Compute the public key y. (b) Encrypt the message M = 8 using the public key above and r = 8. (c) Verify your calculation in part (b) above by decrypting the ciphertext you obtained in part (b)

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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3. In a public key system using Rivest-Shamir-Adlemen (RSA), Eve intercepts a ciphertext C = 33 sent to Alice whose public key is e = 5, n = 35. What is the plaintext M?
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For a block cipher with encryption Ek() and decryption DK(), the equation for the CBC mode of operation is: Cj = EK(Pj e Cj-1). What is the equation for decrypting C?
A.Given p=25, q=9, and e=7, generate the public key (n,e) and the private key (n,d) using the RSA Key generation algorithm. (Use Excel for computations) b. Given Bob's public key of (85, 7) and private key of (85, 55), show how Alice can encrypt m=3 to send to Bob. Show the ciphertext. c. Given Bob's public key of (85, 7) and private key of (85, 55), show how Bob can decrypt the ciphertext y=2 received from Alice. Show the plaintext. d. Using the fast exponentiation method, determine 530 mod 47. Show your work.
Q1 / If you know [k] is key for encryption by hill cipher, and [B] is inverse of [K] and [C] is a result of multiplying [k]*[B], 1- Find the key 2- Encrypt by using hill cipher the text (fourth stage) Solution by Matlab [-0.1389 0.0833 -0.01391 B= 0.0486 -0.2708 0.4201 0.1944 -0.0833 -0.1806]
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Alice and Bod have decided to use a symmetric encryption algorithm. They have some assumptions about their messages:- Messages only contain capital letters (i.e. A to Z)- The length of their shared key must be greater than or equal to the length of the plaintext- They assign each letter a number as follows: (A,0), (B,1), (C,2), (D,3),…, (Z,25)Their algorithm combines the key and the message using modular addition. The numerical values of corresponding message and key letters are added together, modulo 26. For example, if the plain text is “HELLO” and the key is “SECRET” then the encrypted message is calculated as following:Since the length of the plaintext is 5, we just need the first 5 letters of the key (i.e. “SECRE”), then for each letter, we should add corresponding letters in both the plaintext and the key modulo 26.Plaintext: H (7) E (4) L (11) L (11) O (14)Key: S (18) E (4) C (2) R (17) E(4)Cipher: Z (25) I (8) N(13) C(2) S (18) Write a program in Python, C/C++ or JavaScript to…