Bob starts a connection with Alice, not knowing it is actually Trudy pretending to be Alice. During Handshake, Trudy sends him Alice's certificate. When does Bob will realize he is NOT communicating with Alice? When Alice sends the MAC When Alice computes the encryption and MAC keys When Bob receives the MAC When Bob verifies the certificate

Bob starts a connection with Alice, not knowing it is actually Trudy pretending to be Alice. During Handshake, Trudy sends him Alice's certificate. When does Bob will realize he is NOT communicating with Alice? When Alice sends the MAC When Alice computes the encryption and MAC keys When Bob receives the MAC When Bob verifies the certificate

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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Similar questions

On a desktop computer, is it feasible to securely produce secret keys for cryptographic protocols such that they may be used in the protocol?
Please give me correct solution.
5, For the first mode of Message Authentication code (MAC), which description is NOT correct? The key used in this mode is for message encryption. This mode cannot protect message confidentiality. The receiver is able to detect malicious message modification by checking the MAC. The attacker who does not know the key cannot calculate the MAC.
Can an attacker using a MAC modify the Tag (the MAC) and the encrypted data? This attack is hopeless since the recipient can always identify whether the Tag/ciphertext has been tampered with.
Should a nonce be encrypted? O Yes, it prevents the message from being hacked. No, otherwise Bob (the receiver) couldn't read the nonce. O No, and you should never use a nonce in the first place. O Yes, otherwise Oscar (the enemy) would be able to intercept it.
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Do MACs allow attackers to tamper with both the Tag and the encrypted data? Because the receiver can always tell whether the Tag/ciphertext has been tampered with, this attack is useless.
Can a MAC change the Tag and ciphertext while they are in transit? This method doesn't work because the user can always tell when the Tag/ciphertext has been changed.
Encrypt the messageWATCH YOUR STEPby translating the letters into numbers, applying the encryption function f(p) = (−7p+2), and then translatingthe numbers back into letters
Computer science
Suppose Alice has a public key with modulus 815153 and encryption exponent 91. Eve intercepts a ciphertext 766247 from Bob that was encrypted using this key. She calculates 766247 941 (mod 815153)= 143804 and asks Alice to decrypt this message as an authentication test. Alice responds with the decrypted message 167698 Find the plaintext without factoring Alice's modulus.
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…