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 = (P + Ko) 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?

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 = (P + Ko) 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?

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

See similar textbooks

Similar questions

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
Show all of the steps needed to encrypt and decrypt the ASCII message “YES” without a modular arithmetic calculator in an RSA cipher with public key (143, 7).
The Mathematical expression of the encryption and decryption process of a Caesar cipher algorithm is expressed in equations 1 and 2 respectively. c=Ep, k (1) p=Dc,k (2) Draw the flowchart of a Ceasar Cipher cryptosystem. Write a Pseudocode to implement your flowchart in (a
Suppose we have an alphabet of 30 characters, labelled as the integers modulo 30. Suppose that a 2 × 2 affine shift cipher is used to encode a message and it is known that the translation vector B is (0,0). The cipher text comes along as "21, 2, 13, 3, 14, 7, 0, 15,..." and you figure out through some other means that the plaintext starts "15, 16, 1, 1, plaintext? ." What is the encryption key? What are the next four digits of the ....
Consider the affine cipher f(p) = 3p+4 (mod 26), where p is the plaintext representation of the character under consideration. For example the plaintext of the letter A is 0, B is 1, C is 2, ... Z is 25. Use this cipher to encrypt the letters I, N, G, R (changing the numbers back to letters at the end.
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?
Using the concept of Cipher Block Chaining Mode, perform a Simplified DES encryption of a plaintext P=1011111110101011 given K=1111101101 and an Initialization vector 10010011
Use Python scripts or other scripts to solve this.
Note: The notation from this problem is from Understanding Cryptography by Paar and Pelzi. Suppose you have an LFSR with 6 state bits. The first 12 bits of output produced by this LFSR are 101011100010 = 80818283848586878889810811- The first bit produced is the leftmost bit and the bit most recently produced is the rightmost bit. a) What is the initial state of the LFSR? Please enter your answer as unspaced binary digits (e.g. 010101 to represent 85 = 0, $4 = 1, 83 = 0, 82 = 1, 81 = 0, 80 = 1). b) What are the tap bits of the LFSR? Please enter your answer as unspaced binary digits (e.g. 010101 to represent p = 0, P₁ = 1, P3 = 0, P2 = 1, P₁ = 0, Po = 1).
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?
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.
Aes algorithm for symmetric cryptography a) In AES Given the plaintext (000102030405060708090A0B0CEOF) and the key (01010101010101010101010101010101) Show the original contents of State, displayed as a 4x4 matrix