(Chosen Ciphertext Security). Let E = (G,E,D) be a public-key encryption over (M,C). a) Describe the security game of IND-CCA security (hints: slides p22) b) Suppose an active attacker can convert the ciphertext of ?1 = (??:????????@?????, ????) to the ciphertext of ?2 = (??:??????@?????, ????), i.e., given ?1 = ?(??, ?1), the attacker can obtain ?2 = ?(??, ?2), Following the slides p23, show that this encryption algorithm is not CCA secure.

Q: A message authentication code, MAC, takes as input a key K and message M and outputs a tag T. In…

A: The answer is given in step 2.

Q: Implement Playfair Cipher to get the ciphertext. Here, plaintext and key is given. Plaintext =…

A: Plaintext : "Fitness is the key" Since spaces are prohibited, assume plaintext to be :…

Q: Problem #1 Given below is a well-known cryptosystem called affine Caesar cipher, as well as some…

A: One of the earliest and most basic encryption techniques is the Caesar Cipher. It is merely a sort…

Q: Can you mention a reason for using Access Control; i.e. what is the significance of using public or…

A: Since you have asked multiple questions, we will solve the first question for you. If you want any…

Q: Unicity probability for AES exhaustive key search] Consider the bound on the probability that there…

A: SALIENT FEATURES OF AESˆ AES is a block cipher with a block length of 128 bits.ˆ AES allows for…

Q: Problem #1 Given below is a well-known cryptosystem called affine Caesar cipher, as well as some…

A: One of the earliest and most basic encryption techniques is the Caesar Cipher. It is merely a sort…

Q: Write a program that performs the brute-force attack to break the password. The following table…

A: Last digit of CWID Encrypted password 1 indBOW06MoVz6 2 in79RsnfG/VWo 3 inbqJM0dLgWvo 4…

Q: c) Consider a scenario where a fraudulent dealer sends an electronic message to a stock agent,…

A: The Three  main Security Goals Are Confidentiality: Protect the confidentiality of data Integrity:…

Q: Exercise 2 (MAC schemes derived from block ciphers ( Let E denote the family of encryption functions…

A: we assume that it is not collision resistant, i.e. we can find a pain of messages x and y where xty…

Q: ) In the time-variant password authentication method, server B sends a random challenge number c to…

A: By obtaining the value of c and determining h, attacker X is able to successfully impersonate A…

Q: for letter in encrypt: new_position=(alphabets.find(letter)-key)%len(alphabets)…

A: The given code is for security in python language

Q: Problem 1: Implement ElGamal system Your code will accept prime p and a generator a. Then a user…

A: In this question we have to write a python code for implementation of the ElGamal system,…

Q: 1. Alice decides to use the RSA cryptosystem to enable individuals to communicate secret in-…

A: Part (a) - Finding Decryption Exponent (d):Input the RSA public key parameters: N and e.Calculate…

Q: In many cryptographic applications the Modular Inverse is a key operation. This programming problem…

A: Your java program is given below as you required with an output.

Q: - A password is 6 characters in length, and there 17 different characters from which we can select.…

A: Given:

Q: Describe the flaw in this argument: Consider the following attack against one-time pad: upon…

A: According to the information given:- We have to describe the  one-time pad ciphertext.

Q: Consider the following mode of block cipher operation: C₁ = Ex(C-1) @P for i>I Ex(IV) Pi C₁ H where…

A: The given formula for Encryption is as follows: Ci = EK(Ci - 1)⊕Pi  for i > 1 If i = 1, then the…

Q: Question 3: Caesar Cipher we write the message and then shift the alphabet by some specified number…

A: The cryptanalysis is trying, again and again, to decrypt to message, there nothing stops the…

Q: Suppose we have public key encryption system with E the encryption function and Dµ the decryption…

A: Process for authenticating the message using public key k (E k ) and secret key k (Dk).

Q: I need help with number 6 Questtion 3b Consider a simple RSA example. To generate, say, Bob's…

A: The RSA example in question involves generating a key pair for Bob using prime numbers (p=17) and…

Q: Bob wants to securely send a short message to Alice, he is only worried about confidentiality, he…

A: Encryption is the process of converting information or data into a code or cipher that is difficult…

Q: Given P[0..100) of int, determine whether the first 10 values in P are a copy of the last 10 values…

A: Given, P[0..100) of int To determine whether first 10 values in P are copy of last 10 in p we will…

Q: Consider a voting system with 3 candidates C1,C2,C3, and 5 voters V1,V2,V3,V4,V5. The votes will be…

A: To implement a voting scheme that uses the additive homomorphic property of the Paillier PKC, we…

Q: Alice has used Bob's public key (n=93542543, e =9341) to produce a ciphertext C = 72645824 using RSA…

A: RSA Algorithm is developed by Ravist, Shamir, and Adleman. It is Public key encryption asymmetric…

Q: Alice and Bob are strangers. Alice wants Bob to send her a private message A and be able to verify…

A: The answer is given below for the above given question:

Q: [Part C_C1] A source emits messages with probabilities: 0.4, 0.25, 0.15, 0.1, 0.05, and 0.05…

A: Given :    The given probabilities are      p(1)= 0.4 p(2)= 0.25 p(3)=0.15 p(4)=0.1 p(5)=0.05…

Q: Exercise 2 (MAC schemes derived from block ciphers( Let E denote the family of encryption functions…

A: we assume that it is not collision resistant, i.e. we can find a pair of messages x and y where xty…

Q: A password is 4 characters in length,

A: Given condition: We need to choose among:

Q: ) Consider a simple RSA example. To generate, say, Bob's keypair, we select two "large" primes, p=17…

A: The correct solution for the above mentioned question is given in the next steps for your reference

Q: Q2) Suppose that ciphertext C3 is damaged in transmission. Which plaintext blocks become…

A: Solution 1)

Q: Suppose the parameters for an instance of the RSA cryptosystem are N = 17363, e = 5, and d= 10253.…

A: Please refer to the following step for the complete solution of the problem above.

Q: Consider the following encryption scheme for a block cipher (using the notation frequently used in…

A: Cipher Block Chaining : CBC is a headway made on ECB since ECB bargains some security necessities.…

Q: Write a GUI program on Java to play dice games between two players. The game starts with a coin toss…

A: this program provides a basic framework for a simple dice game between two players. You could modify…

Q: A cryptanalyst has determined that the three most common trigraphs in a ciphertext are LME, WRI, and…

A: The answer is

Q: 25, to decrypt the message "DKPG K XCIG HKM".

A: Given:  Decrypt the message " DKPG K XCIG HKM".  Using the encryption function f(x)= (10 - x)mod 26,…

Q: 33. Lamport's one-time password scheme users the passwords in reverse order. Would it not be simpler…

A: First of all let's understand the mechanism of lamport's OTP mechanism.  It use the transforming…

Q: Suppose Alice used a Hash function HA to encrypted her sensitive data. Everyone in the public can…

A: The main purpose of encryption is to protect data confidentially during transmission of data.  So,…

Topological Sort

Topological sort is a sorting technique that sets up a hierarchy in a process. In this technique, when a directed network has nodes connected by arrows, the root node is placed before the successor node.