Alice and Bob are using the ElGamal cipher with the parameters p = 53 and a = 2.Alice makes the mistake of using the same ephemeral key for two plaintexts, x1 and x2. The eavesdropper Eve suspects that x1 = 5. She sees the twociphertexts y1= 41 and y247 in transit; these are the encryptions of a1 and x2, respectively.a) What is the masking key kM?b) What is the plaintext x2?

Data given - . x1 = 5 y1 = 41 y2 = 47 p = 53

Alice and Bob are using the EIGamal cipher with the parameters p = 53 and a = 2. Alice makes the mistake of using the same ephemeral key for two plaintexts, x1 and x2. The eavesdropper Eve suspects that x = 5. She sees the two ciphertexts y1 = 41 and y2 = 47 in transit; these are the encryptions of x1 and x2, respectively. a) What is the masking key kM? b) What is the plaintext x2?

Alice and Bob are using the EIGamal cipher with the parameters p = 53 and a = 2. Alice makes the mistake of using the same ephemeral key for two plaintexts, x1 and x2. The eavesdropper Eve suspects that x = 5. She sees the two ciphertexts y1 = 41 and y2 = 47 in transit; these are the encryptions of x1 and x2, respectively. a) What is the masking key kM? b) What is the plaintext x2?

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

Alice and Bob are using the ElIGamal cipher with the parameters p = 53 and a = 2. Alice makes the mistake of using the same ephemeral key for two plaintexts, x1 and x2. The eavesdropper Eve suspects that x = 5. She sees the two ciphertexts y1 = 41 and y2 = 47 in transit; these are the encryptions of x1 and a2, respectively. a) What is the masking key kM? b) What is the plaintext x2?
t) Alice and Bob are using the ElGamal cipher with the parameters p 173 and a = 2. = Alice makes the mistake of using the same ephemeral key for two plaintexts, ₁ and 2. The eavesdropper Eve suspects that x₁ 169. She sees the two ciphertexts y₁ = 153 and y2 = 135 in transit; these are the encryptions of ₁ and 2, respectively. a) What is the masking key k? = b) What is the plaintext ₂ ?
Encrypt the 12-bit plaintext 101010100111 using Simplified B-DES and the 9-bit key K = 010001111. This is a non-computer problem and you need to show all the steps of the encryption process
Alice sets up an RSA public/private key, but instead of using two primes, she chooses three primes p, q, and r and she uses n=pqr as her RSA-style modulus. She chooses an encryption exponent e and calculates a decryption exponent d. Encryption and Decryption are defined: C ≡ me mod n and m ≡ Cd mod n where C is the ciphertext corresponding to the message m. Decryption: de ≡ 1 mod φ(n) | Let p = 5, q = 7, r = 3, e = 11, and the decryption exponent d = -13. n = 105 & φ(n) = 48 Q: Alice upgrades to three primes that are each 200 digits long. How many digits does n have?
I want Examples on el gamal cipher i want 2 Examples like this Example of ElGamal encryption Alice chooses pA = 107, α A = 2, dA = 67, and she computes β A = 267 ≡ 94 (mod 107). Her public key is ( pA, α A, β A) = (2,67,94), and her private key is dA = 67. Bob wants to send the message "B" (66 in ASCII) to Alice. He chooses a random integer k = 45 and encrypts M = 66 as (r, t) = ( αA k , βA kM) ≡ (245, 944566) ≡ (28, 9) (mod 107). He sends the encrypted message (28, 9) to Alice. Alice receives the message ( r, t) = (28, 9), and using her private key dA = 67 she decrypts to tr−dA = 9⋅28−67 ≡ 9⋅28106−67 ≡ 9⋅43 ≡ 66 (mod 107)
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…
Suppose that Alice and Bob communicate using ElGamal cipher and f (p. 9. Z) is common public values. Bob generates his private key d ER Z and then computes the corresponding and public public key y=g" (mod p). To save time, Bob uses the same number r each time he encrypts a plaintext message m (ie., r is a fixed nonce of Bob, and it is not randomly generated each time encryption is performed). Assume that Alice compute the ciphertext for the message m as (cc) = (g mod p, mxy mod p). and for the message m as (1,2)=(g" mod p, xy' mod p). Show how an adversary who possesses a plaintext-ciphertext pair (m. (c.ca)) can decrypt (1, 2) without knowing the private key d of Bob.
The operator of a Vigenere encryption machine is bored and encrypts a plaintext consisting of the same letter of the alphabet repeated several hundred times. The key is a seven-letter English word. Eve knows that the key is a word but does not yet know its length. What property of the ciphertext will make Eve suspect that the plaintext is one repeated letter and will allow her to guess that the key length is seven? What will the number of matches be for the different displacements?
Alice and Bod have decided to use a symmetric encryption algorithm. They have someassumptions 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 valuesof corresponding message and key letters are added together, modulo 26. For example, if the plaintext 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”), thenfor 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) a) Write a program in Python, C/C++ or JavaScript to…
In an RSA system, the public key (n,e) of a given user is (323, 11). 1. What is the value of the exponent in the private key (n, d), of this user? 2. Suppose you want to send this user the message m = 45, write down the expression to generate the ciphertext for this message. 3. Suppose that your ciphertext, c, is 5, write down the expression to generate the plaintext matching this ciphertext. 4. Can you encrypt the message m=322 with this public key? O a. Yes O b. No
After taking some courses on cryptography, Alice and Bob decide to try it out in their communication. They agree that they will use Vigenere cipher for data encryption/decryption, and RSA for sharing secrete key, where the key of Vigenere cipher only uses letters A, B,..., Jand letters in a key are encoded as digits 0,1,...,9 for RSA. For instance, the key BAJ is 109.Alice chooses a RSA public key (n. e) = (341,7). Bob uses the Vigenere cipher to encrypt a sentence and encrypt the Vigenere key by Alice's RSA public key. Then Bob sends the following message to Alice:61. Tfsgnhgs zq tadnov zuws gutoiosgoz dfiqsk vik ffgfmopf. Ov jy uuxkdz.Answer the following questions:• What is the Nigenere key used by Bob?• What is the original message from Bob?
In the Elgamal encryption scheme, Bob's public key is fixed, but Alice uses a fresh random i e {2,...,p – 2}, and hence a fresh random kg, whenever she wants to send Bob a message. What happens if Alice uses the same i for ecrypting multiple messages? Can Trudy recover any meaningful information from the ciphertexts?