alice wants to send to all her friends, including bob, the message "SELLEVERYTHING" so that be knows that she sent it. What should she send to her friends, assuming she signs the message using the RSA cryptosystem.

Bob's public key is (55,3). Alice wants to send Bob the "message" 6. What is the cyphertext (encrypted version) of her message in the RSA cryptosystem? (Show the arithmetic, and you can use a calculator.)

Using public key cryptography, Bob wants to send a secret message M to Alice (only Alice and Bob should see M), and Alice wants to make sure that M is sent by Bob. Then Bob should: sign the message, and send signature to Alice encrypt M with his public key, encrypt the result with Alice's private key, and then send to Alice Answer is not given encrypt M with his private key, encrypt the result with Alice's public key, and then send to Alice encrypt M with Alice's public key and then send to Alice encrypt M with his public key, encrypt the result with Alice's public key, and then send to Alice encrypt M with his private key, encrypt the result with Alice's private key, and then send to Alice encrypt M with Alice's private key, encrypt the result with his private key, and then send to Alice

A shortcoming of using an elliptic curve E(Fp) for cryptography is the fact that it takes two coordinates to specify a point in E(Fp). However, as discussed briefly at the end of Sect. 6.4.2, the second coordinate actually conveys very little additional information.(b) Alice and Bob decide to use the prime p = 1123 and the elliptic curveE : Y2 = X3 + 54X + 87.Bob sends Alice the x-coordinate x = 278 and the bit β = 0. What point is Bob trying to convey to Alice? What about if instead Bob had sent β = 1?

Alice and Bob agree to use the prime p = 1373 and the base g = 2 for communications using the Elgamal public key cryptosystem. Bob chooses b = 716 as his private key, so his public key is B ≡ 2716 ≡ 469 (mod 1373). Alice encrypts the message m = 583 using the random element k = 877. What is the ciphertext (c1, c2) that Alice sends to Bob?

Bob sent Alice an encrypted message. The message consists of 3 words. In each word, Bob encoded the letters as follows: A = 01, B = 02, C = 03, ..., Z = 26. The he wrote the codes next to each other to form a number that represent the word. For example, the word "WE" is encoded as: 2305 since it consists of 2 letters W=23 and E=05. After encoding, Bob encrypted each encoded word with RSA using Alice public key(pq, e) where p=100000007, q=10000019, e=13. Alice received the following 3 encrypted words from Bob: 451095483713115 570203572152011 958266071840609 She used here RSA private key (d) to decrypt the message. The first word of the message that Bob sent was: WE. Q1. What is the private key d? (enter you answer as an exact number) Q2. What is the second word of the message that Bob sent to Alice? (enter you answer as one word) Q3. What is the third word of the message that Bob sent to Alice? (enter you answer as one word) MATH

Bob sent Alice an encrypted message. The message consists of 3 words. In each word, Bob encoded the letters as follows: A = 01, B = 02, C = 03, ..., Z = 26. The he wrote the codes next to each other to form a number that represent the word. For example, the word "WE" is encoded as: 2305 since it consists of 2 letters W=23 and E=05. After encoding, Bob encrypted each encoded word with RSA using Alice public key(pq, e) where p=100000007, q=10000019, e=13. Alice received the following 3 encrypted words from Bob: 451095483713115 570203572152011 762324289903198 She used here RSA private key (d) to decrypt the message. The first word of the message that Bob sent was: WE.

Bob sent Alice an encrypted message. The message consists of 3 words. In each word, Bob encoded the letters as follows: A = 01, B = 02, C = 03, ., Z = 26. The he wrote the codes next to each other to form a number that represent the word. For example, the word "WE" is encoded as: 2305 since it consists of 2 letters W=23 and E=05. After encoding, Bob encrypted each encoded word with RSA using Alice public key(pq, e) where p=100000007, q=10000019, e=13. Alice received the following 3 encrypted words from Bob: 451095483713115 570203572152011 958266071840609 She used here RSA private key (d) to decrypt the message. The first word of the message that Bob sent was: WE. Q1. What is the private key d? (enter you answer as an éxact number) ord) Q2. What is the second word of the message that Bob sent to Alice? (enter you answer as one Q3. What is the third word of the message that Bob sent to Alice? (enter you answer as one word)

Let's assume that Bob and Alice share a secret key in a symmetric key system. Bob wishes tobegin a conversation with Alice, and sends her a message that essentially says "let's talk". Aliceis suspicious that the person contacting her might not be Bob, so Alice generates a single-userandom number (a nonce) and sends it to Bob. Bob encrypts the nonce with the secret key heshares with Alice and sends it back. Alice decrypts this message and retrieves the same nonceshe sent to Bob. Which of the following is true, provided the secret key K has not been compromised?

In the ElGamal cryptosystem, Alice and Bob use p = 17 and α = 3. Bobchooses his secret to be a = 6, so β = 15. Alice sends the ciphertext (r, t) = (7, 6). Determine the plaintext m.