Suppose Alice and Bob have RSA public keys in a file on a server. They communicate...

Suppose Alice and Bob have RSA public keys in a file on a server. They communicate regularly, using authenticated, confidential message. Eve wants to read the messages but is unable to crack the RSA private keys of Alice and Bob. However, she is able to break into the server and alter the file containing Alice’s and Bob’s public keys.

(1) How should Eve alter the file to so that she can read confidential messages sent between Alice and Bob, and forge messages from either?

(2) How might Alice and/or Bob detect Eve’s subversion of the public keys?

Expert Solution

Answer for question 1:-

Eve can replace their public keys by your own, therefore Bob and Alice will encrypt messages using your public key and eve will be able to decrypt their messages. After eve replaced the public keys Bob and Alice won't be able to decrypt correctly their messages, they may realize quickly that there is a problem with the keys.

Answer For Question 2:-

If Eve fails to intercept a message, the decryption will be found because the message destined for alice and bob will not be decrypted correctly as alice and bob will use their real private keys to decrypt instead of a fake private key. Alice and Bob should regularly check that the public key they have posted on the server is correct. They could also post public key fingerprints at a separate location to encourage individuals to communicate to validate what they receive from the certificate server.

If You have any question, feel free to ask.

Best of luck ?....

venereology answered 4 months ago

RSA: Alice wishes to send Bob the message POET. Suppose Bob chooses P = 29, Q...

RSA: Alice wishes to send Bob the message POET. Suppose Bob chooses P = 29, Q = 31, E = 47, and D = 143. Show the steps that Alice uses to encrypt the message POET (use the ascii values of the letters P, O, E, and T), and how Bob decrypts the message he receives from Alice. You will be generating very large numbers, and will find the following calculator helpful: https://www.calculator.net/big-number-calculator.html

Alice wants to send a plaintext message m = 10 to Bob secretly using RSA public...

Alice wants to send a plaintext message m = 10 to Bob secretly using RSA public key cryptosystem. Bob selects p = 7, and q = 13 with e = 5. You have to perform following tasks: a. Compute and list Bob’s public and private keys. b. Compute the ciphertext that Alice will send to Bob using plaintext message m = 10. c. Recover the actual plaintext from the ciphertext sent by Alice

Alice is sending message “HIDE” to Bob. Perform encryption and decryption using RSA algorithm, with the...

Alice is sending message “HIDE” to Bob. Perform encryption and decryption using RSA algorithm, with the following information: parameters p=11,q=5, e=7 Present all the information that you will need to encrypt and decrypt only the first letter from text

given a hash finction H(), and an RSA encrypting algorithm. The public and private keys for...

given a hash finction H(), and an RSA encrypting algorithm. The public and private keys for Alice are PUa, and PRa, respectively. A. Describe how Alice can produce a digital siguature of a message "M. and how Bob can verify the sigature. B. Does the process described in part (a) above provide authentication? Give reason.

Answer digital signatures question. assume Alice has the RSA key (eA, dA, nA) and Bob has...

Answer digital signatures question. assume Alice has the RSA key (eA, dA, nA) and Bob has the RSA key(eB, dB, nB), where eA, eB, nA, and nB are public, dA is known only to Alice, and dB is known only to Bob. (a) Describe how Alice could use her RSA key to sign a public message m, and explain why this approach satisfies the objective of non repudiation. (b) Describe how Alice could encrypt and send a secret message to...

Suppose Alice flips 4 coins and Bob flips 4 coins. Find the probability that Alice and...

Suppose Alice flips 4 coins and Bob flips 4 coins. Find the probability that Alice and Bob get the exact same number of heads.

How to generate a key pair for Alice and Bob Respectively Suppose Alice sends plaintext P=...

How to generate a key pair for Alice and Bob Respectively Suppose Alice sends plaintext P= 113, how does she encrypt and whats the ciphertext C? After Bob receives C, how does he decrypts it to get the plaintext P? Suppose Alice sends plaintext P= 113, how does she sign it and what are sent to Bob. How does Bob verify the signature? Suppose Bob sends plaintext P=113, how does he sign it and what are sent Alice. How does...

1. Suppose that Alice is rushing past Bob at a velocity u, and she carries with...

1. Suppose that Alice is rushing past Bob at a velocity u, and she carries with her a block of transparent material with index of refraction n. If she shines light through that material then she sees the light moving through it with a velocity c/n. What speed does Bob see the light move through that material? Check that your result has the correct limiting behavior that when n = 1, and u << c/n! 2. An unstable particle of...

Exercise 9.9.1: Breaking RSA by factoring. Bob publishes his public key (e, N) = (109, 221)...

Exercise 9.9.1: Breaking RSA by factoring. Bob publishes his public key (e, N) = (109, 221) (a) Show that if Eve can factor N (N = 13 · 17), then she can determine Bob's private key d. What is Bob's private key? (b) Now suppose that Eve intercepts the message 97. Use Bob's private key to decrypt the message.

Alice and Bob are have several piles of chips. On each turn they can either remove...

Alice and Bob are have several piles of chips. On each turn they can either remove 1 or 2 chips from one pile, or split a pile into two nonempty piles. Players take turns and a player that cannot make a move loses. Find the value of the Sprague–Grundy function for positions with one pile made of n chips. (Please do not forget to prove correctness of your asnwer.)

Question