A secure email system is expected to provide confidentiality, sender's non-repudiation, and message integrity. Alice uses three keys to achieve this goal. The three keys are Alice's private key (KA), Bob's public key (KB+), and a randomly generated symmetric key (Ks). The encryption procedure is shown below: How can Bob 1) decrypt the data, 2) verify the message's integrity, and 3) verify the sender's non- repudiation? Describe the detailed steps (including the formulas) and show your work. KA m➡ HO KA m I am using SHA-256 KA(H(M)) + Ks Ks() + KB(*) Ks Ks(m, KA(H(m)) + + KB(KS) Internet

A secure email system is expected to provide confidentiality, sender's non-repudiation, and message integrity. Alice uses three keys to achieve this goal. The three keys are Alice's private key (KA), Bob's public key (KB+), and a randomly generated symmetric key (Ks). The encryption procedure is shown below: How can Bob 1) decrypt the data, 2) verify the message's integrity, and 3) verify the sender's non- repudiation? Describe the detailed steps (including the formulas) and show your work. KA m➡ HO KA m I am using SHA-256 KA(H(M)) + Ks Ks() + KB(*) Ks Ks(m, KA(H(m)) + + KB(KS) Internet

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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The encryption using the public key is broken down into its component parts here.
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Suppose Alice has a public key with modulus 815153 and encryption exponent 91. Eve intercepts a ciphertext 766247from Bob that was encrypted using this key. She calculates 766247⋅941^91(mod815153)=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.
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Computer Science Assume we use transposition cipher to encrypt the data, and the original message is stored in a 8 by 5 matrix (8 rows and 5 columns). If the ciphertext is shown below, what is the original plaintext?WMHPSCATEEEUCELELTCTIASLOTMRNCA
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.
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Perform Encryption and decryption using the RSA algorithm for the following: a. p=5; q = 11; e = 3; M = 12 b. p= 3; q = 17; e = 7; M = 2 c. p=7; q = 19; e = 11; M = 5 d. p= 7; q = 13; e = 11; M = 8 e. p= 13; q = 23; e = 5; M = 10