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  1. Consider the following pseudo-WEP protocol. The key is 4 bits and the IV is 2 bits. The IV is appended to the end of the key when generating the keystream. Suppose that the shared secret key is 1010. The keystreams for the four possible inputs are as follows: 101000: 0010101101010101001011010100100 . . . 101001: 1010011011001010110100100101101 . . . 101010: 0001101000111100010100101001111 . . . 101011: 1111101010000000101010100010111 . . . Suppose all messages are 8 bits long. Suppose the ICV (integrity check) is 4 bits long, and is calculated by XOR-ing the first 4 bits of data with the last 4 bits of data. Suppose the pseudo-WEP packet consists of three fields: first the IV field, then the message field, and last the ICV field, with some of these fields encrypted. I found the following solution: a. We want to send the message m=10100000 using the IV=11 and using WEP. What will be the values in the three WEP fields? Since IV = 11, the key stream is 111110100000 ………. Given, m = 10100000 Hence, ICV = 1010 XOR 0000 = 1010 The three fields will be: IV: 11 Encrypted message: 10100000 XOR 11111010 = 01011010 Encrypted ICV: 1010 XOR 0000 = 1010 What is the purpose of the key stream? Somebody please guide me. Zulfi.
  2. Hi myfriend- Thanks a lot for your response. I got the code from the following link: https://github.com/Bdragon93/reentrancy-acttack Please check the above image, they have not defined 'c[0]'. My Truffle version: Kindly tell me which version are you talking about? Kindly guide me which tutorial are you using, what is in your 'test' file? Zulfi. Hi fiveworlds- You are right. It was a version problem. Correct: truffle(ganache)> const putAmount = putBalance.toNumber() undefined Zulfi.
  3. Hi, I am trying to run the following code. I am getting error while executing the line: truffle(ganache)> const putAmount = putBalance.c[0] The error is : I have uploaded the image of the whole program. I don't have much knowledge of Javascript. Somebody please guide me how to define the property 'c[0]'. Zulfi.
  4. Hi, I am trying to capture the SSL/TLS packets in the log file. I am following wiki's article but my SSLKeylogfile is empty. I am working in the ubuntu's (18.04) virtual machine. My wireshark version is 3.2.4. I am also attaching an image. Somebody please guide me what is my mistake? Zulfi.
  5. Hi, Thanks for your response. I don't know how can I make buyers satisfactions dependent. I am assuming that buyer's satisfaction depends upon price of the car, outlook of the car and engine of the car based upon the probability values. Please guide me how can I make buyer's satisfactions in a proper manner. I think I am not able to understand this concept properly. Please help me to improve this problem and also my solution in the context of MonteCarlo. Zulfi.
  6. Hi, I want to do capture SSL packet and then decrypt it using wireshark. I saw a video which captures the packets and it shows keyed packets in a video. I have provided a link for the video: I have also attached the image. I want to know how can I decrypt the packets using wireshark? Zulfi.
  7. Hi, I have installed 3.2.4 version of wireshark but in Edit-> Preference->Protocol I can't see the SSL protocol so I selected TLS. Now I can't see nstrace.sskeys in (pre) Master-Secret log filename. I am following the tutorial at: Decrypting SSL and TSL traffic Somebody please guide me is this file necessary for "decrypting SSL and TLS Traffic using wireshark" Zulfi.
  8. Hi, I have a question which I want to solve using MonteCarlo Method Suppose we have a car for sale and a buyer is 65% satisfied with the price of the car, 75% satisfied with the outlook of the car like its body, color, tires and 85% satisfied with the running i.e. the engine? What is the probability that the car would be sold to the said buyer? How we can do a simulation using Monte Carlo Method? I found the answer as: 0.65 * 0.75 * 0.85 = 0.4143 Is this a correct solution? Also please tell me can I use MoteCarlo method for one person? Zulfi.
  9. Hi, I think I have to start as a root. Zulfi.
  10. Hi All, Thanks for your response. First picture is mine. Second one which has the label "Network Analyzer belongs to the tutorial". I am using Ubuntu 18.04. Yesterday I closed it and open several after that I was able to see the correct ports and I was able to do capturing also but today I am seeing the same image as image 1. I have ether0 interface but it was showing me some thing en.. (i think 3 more letters after it). I am watching the videos. I would try some browsing. Zulfi. Hi thanks all, Ghideon your advise was good. I infact installed the wireshark yesterday but some how it was old. I did not check its version. Its on my virtual machine but today some how I installed the wireshark again and its a latest version. I am attaching its image. God blesses you all. Zulfi.
  11. Hi, I am seeing a tutorial, it shows me the interfaces which I have on my computer but wireshark is showing me different interfaces. I have attached the image of both the tutorial and what I am seeing on the wireshark. Somebody please guide me how to select the interfaces related to my computer and how to capture the packets Zulfi.
  12. Hi, I am trying to understand the following question: In a 3-bit block cipher, suppose a sender transmits a cipher text including c(1), r(1), c(2), r(2), c(3), r(3) to a receiver. Find the original plaintext at the receiver. Here c(1) = 100, r(1) = 001, c(2) = 010, r(2)= 111, c(3) = 000, and r(3) = 100. A block cipher encryption key table (Ks) is also shown below: The answer for the first case is: M(1) = Ks(c(1) XOR r(1) = Ks(100) XOR 001 = 010 From the table, the output corresponding to 100 to 011. But the above answer is 010. I can't understand this. Somebody please guide me. Zulfi.
  13. Hi, I was reading an article related to MonteCarlo Method. The link of the article is: http://ib.berkeley.edu/labs/slatkin/eriq/classes/guest_lect/mc_lecture_notes.pdf I found the equation in the following attached image. 1)In the equation related to the attached image, we are assigning a value to a function. What does this mean? 2)What the expected function will do with this value? 3)Please guide me by providing examples of function fX(ꭓ), E(g(X)) and g(ꭓ). Zulfi.
  14. Hi, I am trying to apply PTAS on an algorithm. I think that we apply PTAS on the running time equation of the algorithm. We use the term (1-ϵ) and (1+ ϵ) in the running time of the algorithm but I don’t know how we insert these terms in the running time equation of the algorithm, and that’s what I want to understand. Also how we evaluate the value of ϵ. Let suppose we have a algorithm: M = K * Y Let’s the running time of algorithm is pseudo-polynomial i.e p(n) * K where k and p(n) are polynomial in n. Somebody please guide me. Zulfi.
  15. Hi, I received a response at: https://math.stackexchange.com/questions/3668486/set-cover-problem-how-to-calculate-the-denominator I have following questions: (1)Why start with Z, cost is 7, cost of X is 6, we have to choose the least cost effective? (2) How are we choosing the denominators? In case of Z, denominators are 7, 5, 5, Z has 7 dots (or cardinality) but 5 are shareable and 2 are non-shareable? X has 5 shareable dots, 2 shared with Z and 3 shared with Y, denominators are 3 and 5 how?, Y has 5 elements 3 shareable with X and 2 non-shareable, denominator is 2, why? (3) What is the purpose of these 3 rounds? (4) What is the answer of set Cover? Example says optimal cost is 22? What is the cost in case of greedy algorithm? Somebody please guide me. Zulfi
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